Generated by All in One SEO v4.9.4.1, this is an llms.txt file, used by LLMs to index the site. # VOCAL Technologies Complete Communications Engineering ## Sitemaps - [XML Sitemap](https://vocal.com/sitemap.xml): Contains all public & indexable URLs for this website. ## Pages - [Voice and Data Communications Solutions for Engineers | VOCAL Technologies](https://vocal.com/) - Voice, video, fax, data modem communications and lawful interception software solutions for telephony, mobile, radio and IP networks. Call +1-716-688-4675 today - [Dynamic Connections 26](https://vocal.com/events/dc26/) - VOCAL's Defense & Aerospace communication systems ranges across a broad spectrum of technologies. Call us today for more information! - [Events](https://vocal.com/events/) - VOCALs Caller ID software can be used to generate and detect Calling Identity Delivery. The CID software is compliant with ETSI ES 200 778-1 & ETSI ES 200 778-2 - [Post-Quantum Encryption and VoIP](https://vocal.com/post-quantum-encryption/) - [vIPer Secure Cloud Phone Service | Secure Voice Gateway](https://vocal.com/secure-phone-service/) - The Secure Phone Registrar and Gateway (SPRAG) is a secure phone service for the Sectéra vIPer Phone and other secure phones. SPRAG may be used by public ... - [Private SPRAG Gateway for vIPer Phones](https://vocal.com/private-sprag-on-prem-v150/) - The VOCAL Private SPRAG is a self-contained gateway between Secure Phones (using SIP/V.150.1 protocols) and VoIP telephone systems. - [Defense & Aerospace Technologies](https://vocal.com/defense-aerospace/) - VOCAL's Defense & Aerospace communication systems ranges across a broad spectrum of technologies. Call us today for more information! - [vIPer™ Phone VoIP Solution | V.150 Gateway | STE phones too](https://vocal.com/voip/viper-phones/) - Get vIPer™ and STE phones working without analog lines. Check out our simple solution with an on-site demo. Questions? Contact our experienced engineers today. - [TSVCIS MELPe](https://vocal.com/speech-coders/tsvcis-melpe/) - Based on MELPe, the TSVCIS vocoder provides the framework for improved speech intelligibility, security, and robustness of defense radio communications. - [SCIP (Secure Communications Interoperability Protocol)](https://vocal.com/defense-aerospace/scip/) - The National Security Agency (NSA) developed SCIP to enable interoperable secure comms for the US and its allies, leading to NATO STAC-IS. - [G.729.1 / G.729EV Codec](https://vocal.com/speech-coders/g-729-1-codec/) - G.729.1 / G.729EV vocoder software is optimized for DSPs and conventional processors is used as an internet wideband audio codec for for real-time VoIP applications - [SIP Call Forwarding](https://vocal.com/sip/call-forwarding/) - SIP Call Forwarding is a mechanism for forwarding, or redirection of incoming calls. - [Locating SIP Servers](https://vocal.com/sip/locating-sip-servers/) - SIP defines a mechanism in RFC 3263 "Locating SIP Servers" for determining SIP server locations as well as the transport protocol(s) supported by a server. - [Echo Cancellation](https://vocal.com/echo-cancellation/) - Echo cancellation enhances speech for mobile, voip voice & radio communication applications. Visit us to learn more about our network echo canceller - [Analog Telephone Adapter (ATA) Reference Design](https://vocal.com/ata-analog-telephone-adapter/) - Analog Telephone Adapter (ATA) reference design speeds development of standards-based, next-generation VoIP products for voice, video, fax, and data - [SIP Call Transferring](https://vocal.com/sip/call-transferring/) - SIP Call Transferring provides a mechanism for transferring calls from one User Agent (UA) to another. Contact VOCAL for more information. - [SIP Servers](https://vocal.com/sip/sip-servers/) - VOCAL's SIP software supports several types of SIP servers including proxy, redirect, and registration servers. SIP Servers accept requests and respond to them. - [SIP PRACK](https://vocal.com/sip/prack/) - SIP PRACK (Provisional Response Acknowledgement). Overview. There are two types of responses defined by SIP. They are provisional and final. - [Secure SIP](https://vocal.com/sip/secure-sip/) - VOCAL’s Secure SIP implementation is based on requirements and recommendations specified in RFC3261 and RFC3329. Contact VOCAL for more information. - [Analog Telephone Recorder Reference Design](https://vocal.com/system-designs/analog-telephone-recorder/) - VOCAL's Analog Telephone Recorder monitors calls for voice and fax lawful interception and records up to 4 telephone lines simultaneously - [SIP Presence](https://vocal.com/sip/presence/) - SIP Presence can be defined as the willingness and ability of a user to communicate with other users on the network. Contact VOCAL for more information. - [SIP Trunking](https://vocal.com/sip/sip-trunking/) - SIP trunking is a SIP internet connection between a business IP-PBX and VoIP services of an Internet Telephony Service Provider - [SIP Conferencing](https://vocal.com/sip/conferencing/) - SIP Conferencing is used with VoIP and Voice and Video over IP (VVoIP or V2oIP) to establish a conference session with multiple users. - [Session Initiated Protocol Messaging - SIP Messaging](https://vocal.com/sip/sip-instant-messaging/) - SIP Messaging allows exchanges in Instant Messaging (IM) applications in near real-time between two users. Contact VOCAL for more information. - [Fax over IP (FoIP)](https://vocal.com/voip/fax-over-ip/) - VOCALs Fax over IP and FoIP software solutions enable ordinary group 3 and high speed V.34 fax machines to send facsimiles over the internet using VoIP services - [Session Initiation Protocol (SIP) and Deep Packet Inspection (DPI)](https://vocal.com/sip/sip-deep-packet-inspection/) - Deep Packet Inspection (DPI) of SIP is important for VoIP lawful interception and monitoring scenarios such as session re-negotiation and call forwarding. - [Video PBX Reference Design](https://vocal.com/ata-analog-telephone-adapter/video-pbx-reference-designs/) - Use our Video PBX reference design for cost effective video products with advanced features and functionality. Call to discuss your video requirements. - [SIP Message Routing](https://vocal.com/sip/message-routing/) - SIP Message Routing can be accomplished using different protocols including UDP, TCP, and TLS depending on messaging requirements for reliability and security. - [Frequency Scrambler and Frequency Inversion](https://vocal.com/secure-communication/frequency-scrambler-frequency-inversion/) - Frequency scrambling discourages casual listeners, competitors or others from intercepting sensitive commercial, police and public safety voice communications - [Digital Audio Watermarking](https://vocal.com/audio/digital-audio-watermarking/) - Digital audio watermarking is a method of embedding data into an audio signal, which can later be detected or extracted for verification. - [Automatic Speaker Verification (ASV) Spoofing Attacks](https://vocal.com/speech-processing-and-audio/speaker-verification-spoofing-attacks/) - Speaker Verification Systems can have authentication spoofed in four ways: impersonation, replay, speech synthesis and voice conversion. - [SIP Sessions](https://vocal.com/sip/sessions/) - SIP Sessions are used with VoIP and Voice and Video over IP (VVoIP or V2oIP) to establish a call session between users. Contact VOCAL for more info. - [Time Domain Echo Based Digital Audio Watermarking](https://vocal.com/audio/digital-audio-watermarking/time-domain-echo-based-digital-audio-watermarking/) - Echo Based Audio Watermarking adds watermark data to the host signal by adding echoes, and the watermark can be detected robustly through cepstral analysis. - [Transform Domain Digital Audio Watermarking: Spread Spectrum](https://vocal.com/audio/digital-audio-watermarking/transform-domain-digital-audio-watermarking-spread-spectrum/) - Spread spectrum has foundations in radio communications, but the concepts are easily transferred to audio watermarking. - [Feedback Mitigation - Frequency Suppression](https://vocal.com/echo-cancellation/feedback-mitigation-frequency-suppression/) - A modified spectral subtraction algorithm can be used as an adaptive notch filter to squash the feedback frequencies. Contact us. - [Spatial Audio Introduction](https://vocal.com/resources/research/spatial-audio-introduction/) - Audio played through headphones generally sounds like it originates from inside the listener’s head. VOCAL offers a spatial audio solution which can make an audio signal sound as if it’s coming from any desired direction. - [Rackmount V.150 VoIP to E1/T1 Gateway](https://vocal.com/rackmount-v-150-voip-e1-t1-gateway/) - The VOCAL Embedded TDM SPRAG is a self-contained gateway between Secure Phones (using SIP/V.150.1 protocols) and TDM telephone systems (using PRI/T1/E1 trunks). - [Session Border Controller (SBC) for Air Traffic Control (ATC) ](https://vocal.com/voip/sbc-for-atc/) - An SBC (Session Border Controller) for air traffic control (ATC) is a specialized device that provides secure and resilient voice communication over IP networks, which are replacing older radio systems. - [What is a Session Border Controller? | SBC](https://vocal.com/resources/what-is-session-border-controller-sbc/) - A Session Border Controller (SBC) plays a major role in securing and controlling real-time communications, such as Voice over IP and video conferencing - [Opus Codec](https://vocal.com/speech-coders/opus/) - Opus codec, opus encoder, or opus voice codec is optimized for DSPs & ARM supports both voice & music encoding for VoIP, videoconferencing & HD audio streaming. - [SILK Codec](https://vocal.com/speech-coders/silk/) - VOCAL's SILK vocoder solution for VoIP wideband audio is optimized for real-time multichannel processing on leading DSPs, processors and mobile devices - [iLBC (Internet Low Bitrate) Vocoder](https://vocal.com/speech-coders/ilbc/) - iLBC speech coder software optimized for leading DSPs is used in VoIP, streaming audio, messaging and videoconferencing - [Enhanced Voice Services (EVS) Codec](https://vocal.com/speech-coders/enhanced-voice-services-codec/) - Enhanced Voice Services (EVS), is a multi-rate audio codec supporting an audio bandwidth up to 20kHz with supported use for conversational speech and music. - [Immersive Voice and Audio Services (IVAS) Codec](https://vocal.com/speech-coders/ivas/) - Immersive Voice and Audio Services (IVAS), standardized by 3GPP, is an audio codec supporting mono, stereo, and immersive audio formats. - [Speex Codec](https://vocal.com/speech-coders/speex/) - VOCAL's Speex voice codec software solution for custom HD VoIP and file-based speech compression applications is optimized leading DSPs and processors - [GSM Adaptive Multi-Rate (AMR) Codec](https://vocal.com/speech-coders/gsm-amr/) - GSM AMR voice codec selects the channel and mode settings to deliver optimum speech quality and system capacity. Call to discuss your voice application! - [GSM Enhanced Full Rate (EFR) Codec](https://vocal.com/speech-coders/gsm-efr/) - VOCAL's GSM EFR speech coder is optimized for real-time multichannel processing on leading DSPs and processors. Call to discuss your voice requirements - [GSM Half Rate (HR) Codec](https://vocal.com/speech-coders/gsm-hr/) - GSM HR speech coder is optimized for real-time multichannel processing on DSPs, ARM and other processors. Call to discuss your voice application requirements. - [GSM Full Rate (FR) Codec](https://vocal.com/speech-coders/gsm-fr/) - GSM FR codec software is optimized for real-time multichannel processing on DSP, ARM and other processors. Call to discuss your voice app requirements. - [G.711 Codec - G 711a](https://vocal.com/speech-coders/g-711/) - VOCAL's G 711 Codec software optimized for leading DSPs includes PLC, DTX, VAD and CNG algorithms with optional Acoustic Echo Cancellers. - [ITU G.719 Codec](https://vocal.com/speech-coders/itu-g-719-codec/) - G.719 is a fullband codec designed to be used for both speech and music audio. This codec is well suited for high-fidelity real-time audio communications systems. - [G.728 Codec](https://vocal.com/speech-coders/g-728/) - VOCAL's G.728 LD-CELP vocoder software is optimized for real-time multichannel processing on all major DSPs and processors - [G.726 Codec](https://vocal.com/speech-coders/g-726/) - VOCAL's G.726 vocoder software used in DCME overload channels is optimized for real-time multichannel processing on leading DSPs and processors - [G.723.1 Codec](https://vocal.com/speech-coders/g-723-1/) - G.723.1 Dual Rate voice codec software for multimedia services is optimized for real-time multichannel processing on all major DSPs and processors - [G.722.2 Adaptive Multi-Rate Wideband (AMR-WB)](https://vocal.com/speech-coders/g-722-2-amr/) - VOCAL's G.722.2 AMR-WB codec is suitable for real-time multichannel processing in VoIP application and optimized for leading DSPs and conventional processors - [G.722.1 Codec](https://vocal.com/speech-coders/g-722-1/) - G.722.1 wideband vocoder for hands free HD VoIP is optimized for real-time multichannel processing on leading DSPs and processors - [G.722 Vocoder](https://vocal.com/speech-coders/g-722/) - G.722 wideband voice codec software is optimized for real-time multichannel processing on all leading DSP, RISC, CISC processors and mobile devices - [Other Speech Coders](https://vocal.com/speech-coders/other-vocoders/) - Other speech coders optimized for DSPs include iLBC, MELP, MELPe, speex, LPC-10, CELP, Skype, SILK, Opus are used in military and commercial applications. - [ITU Speech Coders](https://vocal.com/speech-coders/itu-vocoders/) - ITU speech coders optimized for DSPs include G.711, G.721, G.722.2, G.723.1, G.726, G.727, G.728, G.729 used for telephony, satellite and VoIP applications - [GSM Speech Coders](https://vocal.com/speech-coders/gsm-vocoders/) - VOCAL's range of GSM speech coders are suitable for mobile telephony and VoIP applications and optimized for leading DSPs - [G.729 Codec](https://vocal.com/speech-coders/g-729/) - G.729 codec software optimized for leading DSPs and ARM processors supports multichannel operations and G.729 Annexes A-D - [Speech Coder and Compression Software](https://vocal.com/speech-coders/) - VOCAL's Speech Coder Software includes a complete range of speech compression algorithms optimized for execution on ANSI C and leading DSP architectures ... - [MELP Codec](https://vocal.com/speech-coders/melp/) - MELP codec with highly optimized source code for DSPs and ARM is ideal for low-power and low-bandwidth multi-channel applications for mobile, VoIP and radio - [Communication Security Software Library](https://vocal.com/software-modules/communication-security-software/) - VOCAL provides a comprehensive communication security software library to support a variety of secure voice, video fax and data communications over Radio, ... - [LPC-10e Codec](https://vocal.com/speech-coders/lpc-10/) - LPC-10e vocoder software is optimized for leading DSPs and ARM processors, is FS 1015 compliant and supports enhanced LPC-10e. Call us to learn more! - [Analog Modem Adapter with LTE Connectivity](https://vocal.com/voip/analog-modem-adapter-with-lte-connectivity/) - AMA enables POS, telemetry, fax and other analog devices to transmit data over LTE networks. Call to discuss your modem application requirements. - [Careers](https://vocal.com/about-us/careers/) - VOCAL seeks motivated designers with knowledge and experience in telecommunications, networking, hardware and software development, and mathematics and physics - [V.150 Analog Modem Adaptor for Secure Phones](https://vocal.com/v-150-analog-modem-adaptor-for-secure-phones/) - The VOCAL V.150 Analog Modem Adaptor for Secure Phones allows STE users to continue utilizing their devices after traditional copper lines have been removed. - [VoIP Vocoders](https://vocal.com/voip/voip-vocoders/) - VoIP Vocoders used in modern voice communication systems are no longer bound by traditional PSTN limitations as many of today's voice over IP (VoIP) ... - [Video and Voice over IP (VoIP) Decoding](https://vocal.com/lawful-interception/voip-decoding/) - VoIP Decoding extracts audio and video from intercepted VoIP communications sent over mobile, LTE, and other IP networks. VOCAL’s VoIP decoder software may ... - [Embedded Software Modules](https://vocal.com/software-modules/embedded-software-modules/) - Integrated software solutions for voice, video, fax and data. Optimized for DSP, ARM and other processors. Call us to learn more! - [V.150.1 Gateway Solution](https://vocal.com/voip/v-150-1-gateway/) - VOCAL’s V.150.1 Gateway is a standards-based implementation that incorporates reliable and efficient transport of any type of modem signal across IP networks - [Digital Signal Processing (DSP)](https://vocal.com/resources/digital-signal-processing-dsp/) - VOCAL specializes in Audio & Acoustics solutions using Digital Signal Processing with application to voice, video, fax & data communications. Call us today! - [Spatial Sound Demonstration](https://vocal.com/audio-examples/spatial-sound-demonstration/) - Multiple example audio files showing VOCAL’s 3D Spatial Audio library in action. - [Spatial Audio Software](https://vocal.com/speech-processing-and-audio/spatial-audio-software/) - VOCAL’s Spatial Audio system turns a mono audio signal into a stereo audio signal which can be played back through headphones. Its purpose is to modify the original signal in such a way as to make it sound as if it’s originating from a certain direction. - [Active Noise Control / Active Noise Cancellation](https://vocal.com/noise-reduction/active-noise-control/) - Contact us to discuss your active noise control / active noise canecllation application requirements with Vocal Technologies' engineering staff. - [Modem over IP Problems and Solutions and the advent of V.150](https://vocal.com/voip/modem-over-ip-problems-and-solutions/) - Modem over IP provides a solution to connect analog modems to IP networks. V.150 MoIP enables legacy modems to communicate IP over mobile, radio, satellite, etc. - [Wireless Beamforming Techniques](https://vocal.com/beamforming-2/wireless/) - Wireless Beamforming software exploits the MIMO spatial dimension to maximize channel throughput in wireless systems. - [Centered Circular Array Direction of Arrival Estimation](https://vocal.com/beamforming-2/centered-circular-array-direction-of-arrival-estimation-using-least-squares/) - The use of microphone arrays to estimate the DoA of sound sources is widespread. Most algorithms however are tailored for linear array topologies. - [Exploiting Spatial Diversity in Single Antenna Systems](https://vocal.com/beamforming-2/cooperative-communications/) - Cooperative communications is the technique of using relay nodes to take advantage of spatial diversity on devices that are too small for multiple antennas. - [Audio](https://vocal.com/audio/) - Software libraries for superior quality with echo cancellation, noise reduction, beamforming and multi-mic algorithms, optimized for leading architectures. - [Speech Processing & Audio](https://vocal.com/speech-processing-and-audio/) - VOCAL provides Voice design speech processing solutions to support a variety of voice applications & voice communications over radio, mobile, PSTN & IP networks - [Audio Examples](https://vocal.com/audio-examples/) - VOCAL's audio examples demonstrate our echo cancellation and noise cancellation software for improved speech enhancement - [MELPe Codec](https://vocal.com/speech-coders/melpe/) - MELPe codec with highly optimized source code is used in a range of low power and low bandwidth (600 / 1200 / 2400 bps) mobile, VoIP and radio applications. - [The Rust Programming Language as an alternative to C](https://vocal.com/resources/rust-programming-language/) - Rust is quickly becoming relevant in real-time systems, communications and other systems that need secure 24/7/365 uptime. - [About VOCAL Technologies (VOCAL.com)](https://vocal.com/about-us/) - VOCAL Technologies, Ltd. | VOCAL.com, founded in 1986, is dedicated to designing innovative solutions under license for voice, video, data and fax/facsimile - [Supported Processors and Architectures](https://vocal.com/system-designs/supported-platforms/) - VOCAL's software solutions for a wide variety of general purpose and DSP processors are available under license for voice, video, facsimile and data. - [Digital Signal Processing for Hearing Aids](https://vocal.com/resources/digital-signal-processing-dsp/digital-signal-processing-for-hearing-aids/) - [Machine Learning for Optimal and Adaptive Filters](https://vocal.com/echo-cancellation/machine-learning-for-optimal-and-adaptive-filters/) - In this paper, we introduced machine learning algorithms and described how they can be applied to compute optimal and adaptive filters efficiently. - [Acoustic Echo Cancellation: Principles, Challenges, and Advanced Techniques](https://vocal.com/echo-cancellation/acoustic-echo-cancellation-principles-challenges-and-advanced-techniques/) - [Analog Tubes for Infiltrating Spoofing Detection Systems](https://vocal.com/speech-processing-and-audio/analog-tubes-for-infiltrating-spoofing-detection-systems/) - This white paper reviews recent research exploring the use of analog tubes as a physical-layer attack vector against ASI systems - [Covert Speech Recovery via Vibrations: A Review of Eavesdropping Techniques and Real-World Viability](https://vocal.com/secure-communication/covert-speech-recovery-via-vibrations-review-of-eavesdropping-techniques/) - This white paper explores the methods by which these vibration-based attacks can occur and assesses how serious a threat they pose in real-world scenarios - [Understanding Beamforming: A Comprehensive Overview](https://vocal.com/beamforming-2/understanding-beamforming-a-comprehensive-overview/) - Beamforming stands as a cornerstone technology in modern signal processing, enabling targeted signal enhancement and interference mitigation across various wave types - [Acoustic Side-Channel Attacks on Pin Tumbler Locks](https://vocal.com/secure-communication/acoustic-side-channel-attacks-on-pin-tumbler-locks/) - This white paper highlights a significant and previously underappreciated vulnerability in traditional pin tumbler locks: the potential for acoustic side-channel attacks to compromise key security - [Wi-Fi Standards and 802 Amendments:](https://vocal.com/networking/wi-fi-standards-802-ammendments/) - This white paper provides a comprehensive review and analysis of the current and evolving 802.x standards relevant to wireless communication, tracing their historical development and highlighting the key technological advancements that define each generation. - [Adaptive Beamforming via Virtual Microphone Interpolation](https://vocal.com/beamforming-2/adaptive-beamforming-microphone-interpolation/) - This adaptive virtual microphone approach can form a core part of spatial beamforming solutions. By intelligently estimating intermediate pressure points from real sensors, the method can enhance spatial resolution, enable finer directional filtering, and improve perceptual separation of concurrent audio cues. - [Differential Beamforming in 3D:](https://vocal.com/beamforming-2/3d-differential-beamforming/) - Investigating Spatial Gradient Techniques for Directional Sensing in Compact Three-Dimensional Arrays - [Wi-Fi 6 and Wi-Fi 7 (802.11ax and 802.11be):](https://vocal.com/networking/wi-fi-6-7-80211ax-80211be/) - This white paper provides an in-depth examination of the technical advancements and challenges associated with Wi-Fi 6 (802.11ax) and Wi-Fi 7 (802.11be) protocols. - [General Challenges in VoIP:](https://vocal.com/voip/voip-general-challenges/) - Exploring Common Technical and Implementation Hurdles in Modern VoIP Systems - [Enhancing Voice Quality in VoIP and Mobile Networks Using Real-Time Dynamic Range Compression](https://vocal.com/voice-quality-enhancement/enhance-voice-quality-voip-mobile-networks-real-time-dynamic-range-compression/) - This white paper explores the critical role of real-time dynamic range compression (DRC) in mitigating these challenges, thereby enhancing the perceived voice quality in both VoIP and mobile network infrastructures. - [Dynamic Range Compression:](https://vocal.com/voice-quality-enhancement/dynamic-range-compression-principles-practical-implementation/) - Dynamic range compression (DRC) is a crucial audio processing technique that manages the amplitude variations within an audio signal - [Latency and Beamforming Performance:](https://vocal.com/beamforming-2/latency-beamforming-performance/) - An Analysis of How Latency and Related Performance Metrics Impact Beamforming Systems - [Evolution Beyond LTE:](https://vocal.com/5g/evolving-beyond-lte/) - As LTE matures, the industry paves the way for 5G and beyond, where beamforming will redefine network capabilities - [Nearfield Structure of Acoustic Radiation](https://vocal.com/resources/research/nearfield-structure-accoustic-radiation/) - This white paper categorizes the structure of acoustic fields into three distinct zones: the farfield, the nearfield, and the extreme nearfield (also referred to as the evanescent regime). - [Adaptive Beamforming for Echo Cancellation](https://vocal.com/beamforming-2/adaptive-beamforming-echo-cancellation/) - This white explores adaptive beamforming approaches specifically for echo cancellation, focusing on practical applications, performance assessment, and associated challenges. - [Video Research Resources](https://vocal.com/resources/research/video-research/) - VOCAL continues to research issues and uses of advanced technologies for video streaming and voice and video conferencing. Call us today! - [P2P Streaming - P2P Video Streaming](https://vocal.com/video/p2p-video-streaming/) - Peer to Peer Streaming or P2P Streaming and P2P Video Streaming does not need support from Internet routers, making it cost effective and simple to deploy. - [P2P Single Tree Based Video Streaming](https://vocal.com/video/p2p-single-tree-based-video-streaming/) - Single tree-based networks maximize available bandwidth between root and all nodes and respond quickly to node failure. Call to discuss your video app! - [P2P Video on Demand](https://vocal.com/video/p2p-video-on-demand/) - For VoD service, P2P based video streaming can resolve a number of issues. Call to discuss your video streaming requirements. - [Video Streaming to Mobile Devices](https://vocal.com/video/video-streaming-to-mobile-device/) - Video, audio and data streaming to a mobile handset has many challenges to achieve high video quality. Call to discuss your mobile video requirements! - [Adaptive Beamforming for Echo Cancellation](https://vocal.com/resources/research/adaptive-beamforming-for-echo-cancellation/) - Adaptive beamforming is a technique that improves acoustic signal quality by dynamically directing sound while effectively minimizing echoes and reverberations. - [Acoustic Echo Cancellation: Principles, Challenges, and Advanced Techniques](https://vocal.com/resources/research/acoustic-echo-cancellation/) - This white paper explores acoustic echo cancellation (AEC) techniques in human-machine interface systems, including applications such as social robots. - [Linear Constrained Minimum Variance (LCMV) Beamforming](https://vocal.com/beamforming-2/linear-constrained-minimum-variance-lcmv-beamforming/) - Linear constrained Minimum Variance (LCMV) beamforming is a technique widely used in multi-channel acoustic signal processing. - [Audio Processing Design](https://vocal.com/resources/research/audio-processing-design/) - VOCAL's engineering solutions in Audio Processing Design: Beamforming, Speech Processing and Audio, Noise Reduction, etc. - [Current Research](https://vocal.com/resources/research/) - VOCAL Technologies continues to doing research technology and applications of VoIP, voice, video, fax, data and secure communications. Call us to learn more! - [White Papers](https://vocal.com/white-papers/) - White papers and custom software solutions for data/fax modulation, VoIP, VoDSL, systems-on-a-chip, multimedia systems, and networking. - [Acoustic Beamforming Using Different Types of Lenses](https://vocal.com/resources/research/acoustic-beamforming-using-different-types-of-lenses/) - Acoustic beamforming is a technique for controlling the direction and shape of sound waves, enabling targeted delivery and precise sound manipulation. - [Radio over IP (RoIP)](https://vocal.com/voip/roip/) - RoIP transmits radio over IP networks to extend range and interoperability of radio systems. Call to discuss your radio application requirements! - [Methods of Adaptive Beam Focusing](https://vocal.com/resources/research/methods-of-adaptive-beam-focusing/) - Explore adaptive methods for dynamic acoustic beam focusing, a technique used to concentrate sound energy at a specific spatial location by aligning the phases of propagating wavefronts. - [Nearfield Structure of Acoustic Radiation](https://vocal.com/resources/research/nearfield-structure-of-acoustic-radiation/) - This white paper categorizes the structure of acoustic radiation fields into three distinct zones: the farfield, the nearfield, and the extreme nearfield. - [3D Audio Beamforming for Directional Warnings in Headsets](https://vocal.com/resources/research/3d-audio-beamforming-for-directional-warnings-in-headsets/) - Explore the implementation of 3D audio techniques for improving alert systems, ensuring that warnings are spatially accurate within the listener’s headset. - [Comparison of T.38 Transmission Over UDPTL or RTP](https://vocal.com/voip/t-38-over-udptl-rtp/) - T.38 transmission over UDPTL provides simpler implementation with lower overhead while RTP supports secure RTP and data redundancy - [Session Border Controller (SBC)](https://vocal.com/voip/session-border-controller-sbc/) - VOCAL’s Session Border Controller (SBC) facilitates effortless VoIP call management and seamless interoperability built on proven operational reliability. - [Resources](https://vocal.com/resources/) - The following technical information is useful to engineers and developers using VOCAL's software and hardware products and technologies. - [Adaptive beamforming via covariance matrix reconstruction](https://vocal.com/5g/adaptive-beamforming/) - In 5G wireless communications a very large number of antennas are employed at the base station, which provide enough degrees-of-freedom to suppress interference - [Remote Analog Modem Server (RAMS)](https://vocal.com/voip/remote-analog-modem-server-rams/) - VOCAL Remote Analog Modem Server (RAMS) is a solution for inter-operating with legacy modems without the need for modem banks or E1/T1 Remote Access Servers. - [Analog Modem Adapter](https://vocal.com/voip/analog-modem-adapter/) - Analog Modem Adapter enables POS, telemetry, fax and other analog devices to transmit data over IP networks. Call to discuss your modem application requirements - [Analog Audio Over IP (AoIP) - Radio over IP (RoIP)](https://vocal.com/system-designs/analog-over-ip-aoip-gateway/) - AoIP / RoIP Gateway Reference Design - Ideal for RoIP radio interfacing, as well as other analog audio over IP connections using VoIP protocols. - [VoIP Radio Reference Design](https://vocal.com/system-designs/voip-radio/) - VoIP radio software optimized for ARM and other processors enables point-to-point and multi-point voice and data communications over existing RF channels - [RoIP Gateway - Radio Over IP Gateway](https://vocal.com/system-designs/roip-gateway/) - RoIP Gateway or Radio Over IP Gateway enables radio over ip communications between radio systems when distance or terrain make LOS communications impractical. - [Remote Access Server over IP™ (RASoIP™)](https://vocal.com/system-designs/rasoip/) - Remote Access Server over IP (RASoIP) replaces dial-up server gateways with Remote Access Servers for distributed modem networks - [SIP Analog Modem Server (SAMS)](https://vocal.com/voip/sip-analog-modem-server-sams/) - VOCALs SAMS provides an analog data modem replacement that is designed to run over modern Voice over IP networks and operate within cloud environments. - [SIP Analog Modem Server (SAMS) for TTY/TDD](https://vocal.com/voip/sip-analog-modem-server-sams-tty-tdd/) - The VOCAL SAMS for TTY/TDD is a solution for interoperating with legacy modems without the need for modem banks with E1/T1 connections. - [Secure SIP Analog Modem Server (SSAMS)](https://vocal.com/voip/secure-sip-analog-modem-server-ssams/) - The VOCAL Secure SIP Analog Modem Server (SSAMS) offers an added layer of security to SAMS to bridge between legacy analog systems and modern secure telecom. - [MoIP - Modem over IP](https://vocal.com/voip/moip/) - Modem over IP provides a solution to connect analog modems to IP networks. MoIP enables legacy modems to communicate IP over mobile, radio, satellite, etc. - [ED-137 Use Cases](https://vocal.com/voip/roip/ed-137-use-cases/) - These modules need not only be used for ATM purposes any RoIP implementation may benefit from tools that ED 137 supplies for Air Traffic Management System - [ED137 VoIP Air Traffic Management Software](https://vocal.com/voip/roip/ed-137-voip-air-traffic-management/) - ED137 VoIP Radio Air Traffic Management Software Design based on ED 137 / 1B Interoperability Standards for VOIP ATM Radio Components (Vol I) by EUROCAE - [QUIC Protocol](https://vocal.com/voip/quic/) - QUIC (not an acronym) is a transport layer networking protocol implemented with the goals of improving network traffic performance, security, and reliability. - [What is SRTP?](https://vocal.com/resources/development/what-is-srtp/) - Secure Real-time Transport Protocol (SRTP) is an extension to the Real-time Transport Protocol (RTP) that adds confidentiality and message authentication. - [SIP Back-to-Back User Agent (B2BUA)](https://vocal.com/sip/sip-agents/) - SIP agents perform different services for SIP enabled devices in a network. These include user agents, presence agents, back-to-back user agents (B2BUA) - [Contact Us](https://vocal.com/contact-us/) - Learn more about VOCAL's solutions for voice, video, fax and data communications, product licensing, and services or inquire about a custom design - [Beamforming](https://vocal.com/beamforming-2/) - Beamforming software optimized for leading DSPs is used in voice capture and conferencing, ultrasonic imaging, and wireless network communications. - [LANsEND IPv4/IPv6 Network Operating System](https://vocal.com/networking/lansend/) - The LANsEND IPv4/IPv6network operating system provides a framework for application development of network-connected/internet-enabled consumer devices. - [V.151 Gateway](https://vocal.com/voip/v-151-gateway/) - ITU-T V.151 Gateway implementation that incorporates reliable and efficient transport of text-over-IP modem signal across IP networks. - [MVoIP and Mobile VoIP Software](https://vocal.com/voip/mvoip/) - Mobile VoIP software provides a native iPhone/iPad and Android SDK for custom iOS and Android MVoIP apps with VoIP solutions optimized for DSPs & ARM - [V.152 Gateway](https://vocal.com/voip/v-152-gateway/) - ITU-T V.152 Gateway implementation that incorporates reliable and efficient transport of any type of modem signal across IP networks using VBD mode. - [VOCAL's Lawful Interception Software](https://vocal.com/software-modules/lawful-interception-software/) - VOCAL is a leading designer of lawful interception software solutions for voice, video, fax & data communications since 1986. - [SIP Analog Modem Solutions](https://vocal.com/voip/sip-analog-modem-solutions/) - The VOCAL SIP Analog Modem Server (SAMS) and SAMS-for-Facsimile (SAMS-F) fully software solutions enable same interoperability with far end legacy data modems. - [VOCAL Technologies Engineering Services](https://vocal.com/services/) - VOCAL Engineering supports embedded software, custom solutions from initial design, hardware and software development, and integration thru final production. - [Law Enforcement & Enterprise](https://vocal.com/law-enforcement-enterprise/) - VOCAL's law enforcement & enterprise software solutions decode analog & digital voice, fax & data communications as well as provide compliance for ... - [Telecom - IP, PSTN & Mobile](https://vocal.com/telecom/) - Our Telecom solutions are used in a wide range of voice and video conferencing, mobile and radio communications solutions. Contact us for more information! - [Industrial & Automotive Communication](https://vocal.com/industrial-automotive/) - VOCAL's Industrial & Automotive Communication library is used all across the industrial and automotive sectors. Call us for more information! - [IP Communications](https://vocal.com/ip-communications/) - Communication security software library to support a variety of voice, video fax and data communications over Radio, Mobile, Internet and other networks. - [Modem & Fax Software](https://vocal.com/modem-fax-software/) - VOCAL offers a Modem and Fax Software library to support a variety of fax applications and fax communications over Radio, Mobile, & Internet. - [Voice Band Data Demodulation](https://vocal.com/speech-processing-and-audio/voice-band-data-demodulation/) - Voice band modems are used worldwide for commercial, industrial, and military applications, extracting the data within voice band communications is pertinent. - [Request Brochure](https://vocal.com/contact-us/request-brochure/) - Request a brochure for VOCAL's available products. VOCAL provides solutions for voip, voice, video, fax and data telecommunications. - [VoIP Reference Design](https://vocal.com/system-designs/voip-reference-design/) - VOCAL's VoIP Reference Design enables licensee development of customized, standards-based, next-generation Voice over IP products with quick time to market - [Android VoIP SDK](https://vocal.com/voip/android-voip-sdk/) - Android VoIP SDK software speeds app development with native SIP stack, adaptive jitter, WB audio, echo & noise control solutions optimized for ARM & DSPs - [Request a Demo From VOCAL Technologies](https://vocal.com/contact-us/request-demo/) - Request a product demo for Vocal technologies solutions. Use the convenient form or email sales@vocal.com directly. - [Broadband Multiple Linear Point Constraint Design](https://vocal.com/beamforming-2/multiple-linear-point-constraint-design/) - Multiple Linear Point Constraint Design allows users to explicitly specify the response of the beamformer system for different angles and frequencies - [Video Codecs](https://vocal.com/video-codecs/) - Video codecs for still picture, motion video and video conferencing for your multimedia applications. Call to discuss your video requirements! - [Datasheets](https://vocal.com/datasheets/) - VOCAL's Datasheets include Reference Designs, VoIP, speech and video codecs, fax and data modems, security and encryption algorithms - [Acronyms and Abbreviations](https://vocal.com/acronyms-and-abbreviations/) - Acronyms for voice, video, data & fax technology for speech enhancement, acoustic echo cancellation, noise reduction, lawful intercept, & deep packet inspection - [Development Articles](https://vocal.com/resources/development/) - The Bessel and hankel function is a special function in mathematics that expresses inward or outward propagating waveforms. - [Packet Loss Concealment](https://vocal.com/voip/packet-loss-concealment/) - Multiple PLC strategies are used to mitigate audible effects of packet loss in VoIP transmission. Call us to learn more! - [VOCAL.com Complete Website Sitemap](https://vocal.com/vocal-com-sitemap/) - Integrated silicon and software solutions under license for voice, video, data, and facsimile. Browse our complete VOCAL.com sitemap. - [Video Streaming Technology](https://vocal.com/video/video-streaming-technology/) - Video streaming technology enables delivery of audio and video over the Internet to reach many millions of customers. Call to discuss your video application! - [User Adaptive Video Streaming](https://vocal.com/video/user-adaptive-video-streaming/) - Video Streaming leverages a user’s viewing conditions and expected content interaction to improve QoS. Call to discuss your video streaming requirements! - [Scalable Video Encoding](https://vocal.com/video/scalable-video-encoding/) - Scalable video encoding supports HDTV, SDTV, and mobile devices with different resolutions and channels with varying quality levels. Call to learn more! - [Remote Video Surveillance](https://vocal.com/video/remote-video-surveillance/) - Users can view live video surveillance remotely on a PC, laptop, or smartphone anywhere in the world. Call to discuss your remote video application. - [Digital Watermarking](https://vocal.com/video/digital-watermarking/) - Watermarking adds side information (visible, invisible or both) to identify the owner of the source information. Call us to learn how to protect your IP! - [Color Management](https://vocal.com/video/color-management/) - Color management is important to maintain consistent color across different devices. Contact us to discuss your video application requirements. - [VP8 Video Codec](https://vocal.com/video-codecs/vp8/) - VP8 video codec is designed for the internet and newer mobile devices and required for WebRTC. Call to discuss your video application requirements! - [Blocking Artifact Reduction](https://vocal.com/video/blocking-artifact-reduction/) - Video compression algorithms using a block transform can introduce blocking artifacts in the decoded video. Call to discuss your video requirements! - [Digital Telephony](https://vocal.com/telephony-software/digital-telephony/) - Digital telephony is used in the provision of digital telephone services and systems with V.110, V.120, V.14, HDLC, or a direct binary framing layer. - [Analog Telephony](https://vocal.com/telephony-software/analog-telephony/) - VOCAL's telephony software is optimized for execution on DSP architectures from leading silicon suppliers. - [Telephony Software](https://vocal.com/telephony-software/) - VOCAL's telephony software optimized for execution on leading DSP architectures supports legacy telecommunications standards. - [VoIP Gateway Reference Design](https://vocal.com/system-designs/voip-gateway-reference-design/) - VOCAL's VoIP Gateway Design interfaces legacy telephony connections and IP networks with an extensive features list. - [Soft Radio Reference Design](https://vocal.com/system-designs/soft-radio/) - Our radio design supports narrowband FM, FSK and CTCSS & Selcall Signalling for commercial, industrial and other radio applications. Call us today! - [Remote Radio Monitoring](https://vocal.com/system-designs/remote-radio-monitoring/) - Remote radio monitoring uses field deployed devices to intercept low-power radio transmissions in areas with limited power, telephone lines or Internet - [System Designs](https://vocal.com/system-designs/) - VOCAL offers a variety of System Designs to provide voice, video, data, and fax solutions world-wide customized for specific operating environments. - [Speaker Diarization](https://vocal.com/speech-recognition/speaker-diarization/) - Source diarization software with beamforming provides automatic detection, classification, isolation and tracking of speaker in adverse acoustic environments - [Room Quality Modeling](https://vocal.com/speech-recognition/room-quality-modeling/) - Acoustic space models Apparent Source Width, Clarity, Reverberance, Loudness, Intimacy, Warmth, Brilliance, Spaciousness, Localization, and Intelligibility - [Microphone Array Aided Distant Speech Recognition](https://vocal.com/speech-recognition/microphone-array-aided-distant-speech-recognition/) - DSR systems use microphone arrays to significantly reduce WER and provide a more natural human-computer interface. Contact us to learn more! - [Machine Learning Algorithms](https://vocal.com/speech-recognition/machine-learning-algorithms/) - VOCAL's robust machine learning software algorithms provide optimal and adaptive speech processing discriminants for crisp audio across any environment. - [G.729A Codec](https://vocal.com/speech-coders/g-729a/) - G.729A vocoder software optimized for DSPs and conventional processors is used as an internet wideband audio codec for VoIP and multimedia applications - [Fractional Resampling](https://vocal.com/speech-coders/fractional-resampling/) - VOCAL's Fractional Resampling software is used to change the signal sampling rate while avoiding imaging and aliasing - [Audio Sample Rate Converter](https://vocal.com/speech-coders/audio-sample-rate-converter/) - VOCAL's Sample Rate Converter reduces the audio sampling rate and computational burden of signal processing with minimal loss of signal information. - [Allpass Filters in Vocoders](https://vocal.com/speech-coders/allpass-filters/) - Vocoders use Allpass filters to modify a signal without attenuating any of its frequencies and to convert between sampling rates, e.g. wide to narrowband - [Specialty Technologies](https://vocal.com/specialties/) - VOCAL Specialties include acoustic beamforming, advanced error coding, cryptographic system design, lawful interception, and related patents - [Search Results](https://vocal.com/search-results/) - VOCAL is dedicated to providing superior hardware and software solutions to meet our customer's voice, video, data, and facsimile (fax) needs. - [Voice](https://vocal.com/resources/research/voice/) - VOCAL continues to research issues and uses of advanced technologies for speech enhancement in voice communications. Call us today! - [GStreamer Debugging Tools](https://vocal.com/resources/research/video-research/gstreamer-debugging-tools/) - GStreamer is a cross-platform multimedia framework that sits between the user application and the low-level operating system APIs for audio and video hardware. - [Fax](https://vocal.com/resources/research/fax/) - VOCAL continues to research issues and uses of advanced technologies for fax communications. Call us today! - [Communication Security](https://vocal.com/resources/research/communication-security/) - VOCAL continues to research issues and uses of advanced technologies for secure communication of voice, video, fax and data communications. Call us today! - [Video Reference Designs](https://vocal.com/resources/reference-designs/video-reference-design/) - Our Video Reference Designs support video streaming, voice and video conferencing and other multi-media applications. Contact us today! - [Press Releases](https://vocal.com/press-releases/) - VOCAL Technologies Ltd. Press Releases and latest developments from the year 1994 to today at VOCAL.com. Read about what's new and upcoming at VOCAL.com. - [NASA Award of Recognition for Artemis I Contributions](https://vocal.com/presentation-of-the-award-on-august-23-2023/) - VOCAL supplied NASA with Speech Coding, Voice over IP and Echo Cancellation solutions for the Orion Spacecraft, the Artemis Program and the Advanced Space Suit. - [Time Scale Modification](https://vocal.com/perceptual-filtering/time-scale/) - Algorithms used to modify time scales of speech must also adjust for pitch changes with phase changes - [Phase Reconstruction](https://vocal.com/perceptual-filtering/phase-reconstruction/) - In Speech Enhancement, phase reconstruction is used to reconstruct the spectrum of the enhanced speech from the received signal - [Particle Swarm Optimization](https://vocal.com/particle-swarm-optimization/) - VOCAL's Particle Swarm Optimization algorithms are essential to echo cancellation, noise reduction, beamforming, and adaptive filters for speech enhancement. - [Dual Microphone Adaptive Noise Reduction](https://vocal.com/noise-reduction/adaptive-noise-reduction/) - With the aid of speech enhancement and noise reduction techniques the clarity and quality of speech communication and recognition systems can be improved. - [TR-111](https://vocal.com/networking/tr-111/) - Technical Report 111 (TR-111) allows the remote management of home networking devices through NAT traversal mechanisms, as defined in TR-069 Annex G. - [Nat/Firewall Software](https://vocal.com/networking/natfirewall-support/) - VOCAL's NAT/Firewall software permits user apps to safely communicate with other user apps through NAT/firewalls. - [Internet Protocol Security (IPsec)](https://vocal.com/networking/ipsec/) - VOCALs IPsec algorithm optimized for leading DSPs provides secure IP connections for IPv4 and IPv6 Native, BITS, and BITW implementations - [Dynamic Directional RTS/CTS](https://vocal.com/networking/dynamic-directional-rtscts/) - VOCAL's use of Dynamic Directional RTS/CTS reduces interference between network stations and avoid data collisions to improve overall network throughput - [Networking](https://vocal.com/networking/) - Network solutions and expertise to design an architecture for your LAN, WAN and WLAN topology with optimized throughput and QoS for your system - [Sitemap](https://vocal.com/html-sitemap/) - Browse our complete sitemap of topics available for you. Call to discuss your voice, video, fax and data application requirements. - [FPGA/PLD/ASIC Cores](https://vocal.com/hardware-reference-designs/fpgapldasic-cores/) - VOCAL's reference designs are available for licensing as software or hardware/firmware formats including FPGA/PLD/ASIC IP Cores - [Hardware Reference Designs](https://vocal.com/hardware-reference-designs/) - Voice, Video, Data, and Fax Hardware Reference Designs for world-wide use and customizable for specific operating environments. - [Fax over IP Server Software Library (FXSRV)](https://vocal.com/fax-over-ip-server-library-fxsrv/) - VOCAL’s Fax over IP Software Server Library is designed to allow Linux and Windows developers the ability to create fax endpoints supporting both T.38 and T.30. - [Stability Control by Echo Canceller](https://vocal.com/echo-cancellation/stability-control-by-echo-canceller/) - Stability control of echo canceller based systems in closed loop systems prevents high-level oscillations or singing. Contact us today! - [Sparse Echo Cancellers](https://vocal.com/echo-cancellation/sparse-echo-cancellers/) - Sparse Echo Cancellers are used where the echo path impulse response is relatively short and the high energy clusters are sparsely distributed. Call us today - [Potential Instability of NE/FE System with Echo Cancellation](https://vocal.com/echo-cancellation/potential-instability-of-nefe-system-with-echo-cancellation/) - Near-End/Far-End systems with terminating echo cancellers (LNEC or AEC) at both ends of the voice channel are potentially unstable. Call us today! - [Line / Network Echo Canceller](https://vocal.com/echo-cancellation/line-network-echo-canceller/) - In telecommunications, Line/Network Echo Cancellers remove audible echoes caused by electric signal reflections from telephone hybrid circuits - [G.167 Acoustic Echo Canceller](https://vocal.com/echo-cancellation/g-167-acoustic-echo-canceller/) - VOCAL’s G.167 Acoustic Echo Canceller (AEC) is designed to cancel acoustic feedback between a speaker and a microphone in speakerphone audio systems - [Far-End Line Echo Canceller](https://vocal.com/echo-cancellation/far-end-line-echo-canceller/) - VOCALs Far end line echo canceller, optimized for DSPs, cancels echo at the near end in the signal received from the far end - [Anti-howling](https://vocal.com/echo-cancellation/anti-howling-software/) - Anti-howling software can be use prevent howling and feedback issues caused by closed acoustic loops. - [Room Reflections](https://vocal.com/dereverberation/room-reflections/) - The amplitude and phase of a reflected signal can vary according to distance, wavelength and angle of incidence and absorption coefficient for each surface - [Speech & Voice Reverberation](https://vocal.com/dereverberation/reverberation/) - Speech reverberation is a significant problem for speech enhancement in videoconferencing, laptop and tablet communications systems - [Data Protocol Software](https://vocal.com/data-modem/data-protocols/) - Data protocol software is part of our comprehensive and fully optimized modem software library. Contact VOCAL for more information. - [Data Modulation Software](https://vocal.com/data-modem/data-modulations/) - Data modulation software for V.92 and V.90 (client/server), V.34, V.32bis/V.32, V.22bis/V.22, V.23 and V.21 modems optimized for leading DSPs - [SEED](https://vocal.com/cryptography/seed/) - VOCAL's SEED cryptographic algorithm is robust differential cryptanalysis, linear cryptanalysis, and related key attacks. - [Video Solutions](https://vocal.com/contact-us/video-solutions/) - Video Design solutions for rapid development of video applications include Video surveillance, Video conferencing, and custom video solutions available - [Noise Reduction Solutions](https://vocal.com/contact-us/noise-reduction-solutions/) - Noise Reduction for military, industrial and commercial voice communications in cockpits, call centers, and other challenging environments. Call today! - [Ask the Experts](https://vocal.com/contact-us/ask-the-experts/) - Ask us a question! One of our expert engineers will answer your technical questions promptly. Contact us today! - [Compressed Sensing of Images](https://vocal.com/compressed-sensing/images/) - Compressed sensing is used to simplify the sampling procedure for complex imaging systems such as MRI and extremely high resolution optical imaging. - [Block Diagrams](https://vocal.com/block-diagrams/) - VOCAL's reference designs include ATA, PBX, MGCP, routers, and fax/data modem modulations and pumps for VoIP, FoIP and MoIP applications - [Time Delay Estimation](https://vocal.com/blind-signal-separation/time-delay-estimation/) - In signal processing, we often encounter problems that the time delay of a signal is required to perform certain operation. - [Correlation Techniques](https://vocal.com/blind-signal-separation/correlation-techniques/) - In audio or speech signal processing, we often encounter signal lineup problems. They can happen in either time or frequency domains. - [Blind Source Separation for Noise Reduction in Mobile](https://vocal.com/blind-signal-separation/blind-source-separation-for-noise-reduction-in-mobile/) - BSS methods of noise reduction are ideal for mobile telecommunications, such as cellular phones/smart phones with microphone arrays. Contact us today! - [Blind Signal Separation (BSS)](https://vocal.com/blind-signal-separation/) - Blind Signal Separation (BSS) is used in many digital signal processing applications where signal separation using blind methods is applicable. - [Beamforming Techniques](https://vocal.com/beamforming-2/techniques/) - VOCAL's beamforming software supports classical, statistically optimal and adaptive beamforming methods for different application requirements - [Nth order endfire beamformer](https://vocal.com/beamforming-2/nth-order-endfire-beamformer/) - Cascading first order differential beamformers together can be done to synthesize a single output. Call to discuss your beamforming application requirements. - [Microphone Array Technologies](https://vocal.com/beamforming-2/microphone-array-technologies/) - VOCAL Technologies provides microphone array algorithm solutions to fir individual requirements, using custom build solutions to solve common problems. - [Microphone Arrays](https://vocal.com/beamforming-2/microphone-array-beamforming/) - Microphone array beamforming results in reduced interference and improved quality of the captured sound. Call for VOCAL more information. - [Frost Beamformer](https://vocal.com/beamforming-2/frost-beamformer/) - Our Frost Beamformer used for speech enhancement readily adapts to variations in room acoustic reverberation time and is immune to reverberation. - [Frequency Domain Beamforming](https://vocal.com/beamforming-2/frequency-domain-beamforming/) - The short microphone spacing in microphone array has always been a problem for beamforming algorithm designers. - [Directional beamforming using two microphones](https://vocal.com/beamforming-2/directional-beamforming-using-two-microphonesdirectional-beamforming-using-two-microphones/) - VOCAL uses a coherence based directional beamforming approach which removes the limitations in classical angle of arrival approaches for two microphones. - [Adaptive Beamforming using MUSIC Pseudo-Spectrum](https://vocal.com/beamforming-2/adaptive-beamforming-using-music-pseudo-spectrum/) - Adaptive beamformers enhance a desired signal while suppressing noise and interference at the output of an array of sensors. Call us today at 1-716-688-4675! - [Acoustic Beamformer](https://vocal.com/beamforming-2/acoustic-beamformer/) - An Acoustic Beamformer will increase the signal from desired direction versus signal from undesired direction. - [Speech Coder Audio Examples](https://vocal.com/audio-examples/speech-coder-audio-examples/) - VOCAL's Speech Coder software libraries optimized for leading DSPs support ITU, GSM, Wideband and other special purpose vocoders - [VPBX Home Gateway Reference Design](https://vocal.com/ata-analog-telephone-adapter/vpbx-home-gateway-reference-design/) - VOCAL's VPBX Home Gateway Reference Design optimized for leading DSPs uses VoIP, HPNA and Internet to meet all of a household's telephony needs. - [Video PBX Design Features](https://vocal.com/ata-analog-telephone-adapter/video-pbx-features/) - VOCAL's Video PBX Reference Design optimized for leading DSPs features standard telephony, video conferencing and streaming video - [Assured Services Session Initiation Protocol (AS-SIP)](https://vocal.com/as-sip/) - Assured Services Session Initiation Protocol (AS-SIP) is the DoD Information System Network’s standard session initiation protocol. - [Tradeshows & Conferences](https://vocal.com/about-us/tradeshows/) - VOCAL is a regular attendee at a variety of conferences and tradeshows. Read about some of our past tradeshows. Hope to see you there in the future. - [Privacy Policy](https://vocal.com/about-us/privacy-policy/) - The privacy of our customers is important to us. Information you provide us via our website is protected according to this policy. - [Terms of Use](https://vocal.com/about-us/terms-of-use/) - Use of this website constitutes your acceptance of this copyright statement and terms of use (collectively, “Terms of Use”). - [Patents](https://vocal.com/about-us/patents/) - VOCAL has developed and patented a variety of industry-critical technologies. This list identifies several of the patents which have already issued or published - [Partners](https://vocal.com/about-us/partners/) - VOCAL collaborates with our partners to design next generation telecommunications applications for voice, video, fax and data - [VOCAL's Voice Reference Designs](https://vocal.com/resources/reference-designs/voice/) - Voice Reference Designs for turn-key and custom solutions for a range of analog, radio, mobile and IP network applications. Contact us to learn more! - [T.38 Fax Image Decoding](https://vocal.com/specialties/t-38-image-extraction-library/) - T.38 Fax Decoding Software optimized for DSPs extracts V.34 & V.17 fax images from recorded and real-time sniffer T.38 Fax over IP frame capture sources - [Lawful Interception](https://vocal.com/lawful-interception/) - VOCAL's Lawful Interception solutions are available for voice, video, fax/facsimile and data communications, including ... - [Acoustic Beamforming Algorithms](https://vocal.com/beamforming-2/acoustic-beamforming-algorithms/) - Acoustic beamforming algorithms are applicable to a wide range of microphone arrays that exist in reverberation environments. - [SIP Analog Modem Server - Alarm Panels](https://vocal.com/voip/sip-analog-modem-server-alarm-panels/) - Data Modem Server for data center, VM or Cloud using SIP. Replace old hardware modem servers and phone lines, while still connecting to an existing alarm panel. - [SAMS MV-90 xi Meter Polling](https://vocal.com/voip/sams-mv-90-xi-meter-polling/) - SAMS MV-90 xi Meter Polling provides a fully software-based solution for polling traditional analog data modems. Contact VOCAL for more information. - [TSVCIS Cryptographic Features](https://vocal.com/speech-coders/tsvcis-melpe/tsvcis-cryptographic-features/) - TSVCIS uses the Commercial National Security Algorithm (CNSA) for robust security of next generation tactical secure voice radios. - [DSP links](https://vocal.com/resources/dsp-links/) - Since 1986 VOCAL has been a leader in researching and developing software for embedded systems and DSPs. Call us to learn more! - [Voice Design Solutions](https://vocal.com/voice/) - VOCAL provides a broad range of Voice Design Solutions to support a variety of voice applications as well as voice communications over Radio, Mobile, PSTN and.. - [Echo Cancellation Software](https://vocal.com/software-modules/echo-cancellation-software/) - Echo Cancellation software is used for speech enhancement in a wide range of Radio, Mobile, VoIP and Voice applications. Call us to learn more! - [VOCAL's Supported Operating Systems](https://vocal.com/system-designs/supported-operating-systems/) - VOCAL's optimized software solutions support UNIX, Linux, Microsoft Windows, Symbian, Mac, VxWorks and Integrity Operating Systems - [Secure Real Time Transport Protocol - Secure RTP](https://vocal.com/voip/srtp/) - SRTP, or Secure Real Time Transport Protocol, or Secure RTP software provides confidentiality, message authentication and replay protection for RTP and RTCP. - [WebSockets and SIP over WebSockets](https://vocal.com/webrtc/websockets-and-sip-over-websockets/) - The WebSockets protocol enables applications running inside web browsers to open up two way communications. The SIP over WebSockets protocol extends the SIP ... - [WebRTC Communications Security](https://vocal.com/webrtc/webrtc-communications-security/) - WebRTC Communications Security protocols ensure user's communications cannot be intercepted by third parties. Call to discuss your WebRTC security requirements! - [Real Time Streaming Protocol - RTSP](https://vocal.com/v2oip/rtsp/) - RTSP Protocol or Real Time Streaming Protocol is used to establish and control media sessions for audio and video streaming between end points. - [V.21 Channel 2 Fax Software](https://vocal.com/fax-modem/v-21-channel-2/) - V.21 Channel 2 fax software optimized for DSPs supports low data rate 300 bps duplex modem transmissions on switched telephone networks - [V.27ter Fax Software](https://vocal.com/fax-modem/v-27/) - V.27ter fax software optimized for DSPs and ARM implements a 4800/2400 bps duplex modem for switched telephone networks. Contact us for more information. - [V.29 Fax Software](https://vocal.com/fax-modem/v-29/) - V.29 fax software optimized for DSPs and ARM supports 9600 bps modem modulations and operating sequences for 4-wire telephony circuits - [Software Modules](https://vocal.com/software-modules/) - VOCAL's integrated software modules for VoIP, voice, video, data, and facsimile embedded applications are optimized for ANSI C and leading DSP platforms - [Fax Protocol Software](https://vocal.com/fax-modem/fax-protocols/) - Fax Protocol software optimized for leading DSPs supports Group 3 V.17, V.29, and V.34 fax withT.4, T.6, and T.30 protocol stacks ... - [Fax Modulation](https://vocal.com/fax-modem/fax-modulations/) - Group 3 V.34 fax, V.17, V.29, V.27ter, V.21 channel 2 Fax modulation software optimized for DSPs and ARM. Call to discuss your fax requirements - [T.38 Fax over IP Software Solution](https://vocal.com/voip/t-38-fax/) - VOCAL offers T.38 Fax over IP software that may be licensed by developers or especially part of a complete design. Contact us for more information! - [Fax Command Set Software](https://vocal.com/fax-modem/fax-command-set/) - Fax Command Set Controller software optimized for DSPs and ARM includes Service Class 1 controls for fax modulations and Class 2 for T.30 functions ... - [Automatic Gain Control](https://vocal.com/automatic-gain-control/) - Automatic Gain Control (AGC) is typically one of the last Voice Quality Enhancement (VQE) blocks of the transmit path of the microphone signal. - [WebRTC Enabled VoIP Endpoints](https://vocal.com/webrtc/webrtc-enabled-voip-endpoints/) - WebRTC Enabled VoIP Endpoints incorporate the WebRTC standards to allow direct communication with WebRTC embedded endpoints from web based applications. - [Session Description Protocol - SDP Protocol](https://vocal.com/voip/sdp/) - What is SDP? Session Description Protocol, or SDP Protocol, describes multimedia sessions, including media type & supported codecs, for Internet telephony calls - [MGCP - Media Gateway Control Protocol](https://vocal.com/voip/mgcp/) - MGCP, or Media Gateway Control Protocol, provides conversion between audio sent on telephone circuits & VoIP data packets transmitted on IP & packet networks. - [Real Time Transport Protocol (RTP)](https://vocal.com/voip/rtp/) - The Real-Time Transport Protocol (RTP) is used to transmit audio, video and other media/data streams for real-time applications such as RTSP media streaming... - [V.34 Fax Software](https://vocal.com/fax-modem/v-34-fax/) - V.34 Fax modem software optimized for DSPs and ARM supports both full and half duplex high speed fax/facsimile transfers up to 33.6 kbps - [Jitter Buffer for Voice over IP](https://vocal.com/voip/jitter-buffer-for-voice-over-ip/) - VoIP systems improve voice quality by using an adaptive jitter buffer algorithm to compensate for late, out of order, or lost packets. Contact us to learn more! - [CVSD Codec - Continuously Variable Slope Delta](https://vocal.com/speech-coders/cvsd/) - CVSD Codec, or Continuously Variable Slope Delta, modulation is a codec which was designed for use in military wireless communication systems. - [G.168 Line Echo Canceller Software](https://vocal.com/echo-cancellation/g-168-lec-software/) - VOCAL's G.168 Line Echo Canceller meets standard ITU and rigorous proprietary testing for world-class performance. Call us to learn more! - [V.17 Fax Software](https://vocal.com/fax-modem/v-17/) - V.17 fax software optimized for leading DSPs and ARM provides V.17 protocols and modulations for high speed 14.4kbps fax/facsimile modems ... - [T.30 Fax Software](https://vocal.com/fax-modem/t-30-protocol/) - T.30 fax software optimized for leading DSPs provides V.21, V.27ter, V.29, V.17 and V.34 Group 3 facsimile control using the T30 protocol - [Fax Monitoring and Diagnostics](https://vocal.com/fax-modem/fax-monitoring-and-diagnostics/) - Diagnostics and statistics support system analysis, monitoring and network bandwidth management. Call to discuss your fax application requirements! - [Video Design Solutions](https://vocal.com/video/) - VOCAL provides a broad range of Video design solutions to support a variety of video applications from video streaming, video security and surveillance to ... - [Secure Communication](https://vocal.com/secure-communication/) - VOCAL provides a range of secure communication solutions with private and public key cryptography for communications security over public and local networks - [HD Video Reference Design](https://vocal.com/system-designs/hd-video/) - VOCAL‘s HD Video reference design supports rapid development of point to point and multipoint high definition video conferencing and communications .... - [Fax Demodulator and Fax Decoder](https://vocal.com/fax-modem/fax-demodulator-fax-decoder/) - Fax Demodulator and Fax Decoder software converts Group 3 high speed V.34 and low speed fax audio to image files for both standard and non-standard machines - [Data Modem Solutions](https://vocal.com/data-modem/) - VOCAL's Data Modem Solutions comprise a range of data modulations and protocols for legacy modem applications and modem communications over PSTN, Radio, ... - [Video Software Library](https://vocal.com/software-modules/video-software/) - VOCAL's comprehensive Video software library can be used for a range of video communications applications from video surveillance to video teleconferencing ... - [Speech Recognition](https://vocal.com/speech-recognition/) - Speech recognition is of great interest to the world of academics and industry. There are two main classes of speech recognition systems - connected speech ... - [Point of Sale Modem Support on VoIP Networks](https://vocal.com/voip/point-of-sale-modem-support-on-voip-networks/) - Point of Sale payment processing is a perfect candidate for migration to Voice over Internet Protocol (VoIP) based Payment Processing technology. - [Radio Software Library](https://vocal.com/software-modules/radio-software/) - VOCAL provides a comprehensive Radio software library to support a variety of radio applications and radio communications over Radio, Mobile and other ... - [VoIP Stack Featuring Voice Quality Enhancement (VQE)](https://vocal.com/voice-quality-enhancement/voip-stack-featuring-vqe/) - VOCAL's VoIP stack features voice quality enhancement with speech coders, AEC, NR, RTP, and SIP signaling with custom VoIP solutions optimized for DSPs & ARM - [DM8168 Video Software and Framework](https://vocal.com/system-designs/dm8168-dm8148-video-framework/) - DM8168 Video Framework unlocks simultaneous SD & HD video channel capabilities of DM8168 & DM8148 media processors. Call to discuss your video application. - [Fax Modem Software Library](https://vocal.com/software-modules/fax-modem-software/) - VOCAL provides a comprehensive Fax Modem software library to support a variety of fax applications and fax communications over Radio, Mobile, Internet etc. - [Voice and Video over IP (V2oIP) Software](https://vocal.com/v2oip/) - V2oIP software libraries provide the foundation for our video reference designs, offering licensees a complete voice and video over IP solution. - [VoIP Software - Voice Over IP Software](https://vocal.com/software-modules/voip-software/) - Learn about our full range of VoIP software. VOCAL is a leading designer of Voice Over IP Software solutions for mobile, radio & IP networks. - [Voice Processing](https://vocal.com/voice-processing/) - VOCAL provides a broad range of Voice processing design solutions to support a variety of applications as well as voice communications over radio, mobile, ... - [Background Noise Reduction](https://vocal.com/noise-reduction/) - Background Noise reduction Software solutions for Single-Channel, Multi-Channel and Microphone Arrays optimized for leading DSPs and microprocessors. - [Session Initiation Protocol - SIP Protocol](https://vocal.com/sip/) - VOCAL's Session Initiation Protocol (SIP Protocol) Software Library implements RFC 3261 with full support for SIP client and server applications. - [Data Modem Software](https://vocal.com/software-modules/data-modem-software/) - VOCAL provides a comprehensive Data Modem Software Library to support a variety of legacy data modem applications and modem communications over Radio, Mobile... - [Multi Mic Audio Signal Processing](https://vocal.com/beamforming-2/multi-mic-audio-signal-processing/) - Multi mic audio signal processing is a digital signal processing solution for enhancing an audio signal of interest over competing audio sources. Multiple ... - [Web Real Time Communications (WebRTC)](https://vocal.com/webrtc/) - WebRTC enables web applications to send and receive audio, video, and data in real time. Call to discuss your realtime web communication requirements! - [Voice Software Library](https://vocal.com/software-modules/voice-software/) - Read more about our voice software. VOCAL is a leading designer of voice telephony software and voice communications solutions since 1986. Call us today! - [Dereverberation](https://vocal.com/dereverberation/) - VOCAL's dereverberation software, optimized for DSP & ARM, removes echo, noise & reverberation effects from speech signals to improve speech intelligibility - [Voice Enhancement - Voice Quality Enhancement (VQE)](https://vocal.com/voice-quality-enhancement/) - Voice Enhancement or Voice Quality Enhancement (VQE) removes echo & noise and adjusts speech levels for superior speech & ISR solutions optimized for DSPs & ARM - [Fax Modem Solutions](https://vocal.com/fax-modem/) - VOCAL's Fax Modem Solutions provide a range of fax modulations and protocols for a variety of facsimile applications and fax communications over Internet, ... - [Voice Over IP (VoIP)](https://vocal.com/voip/) - VoIP enables telephone, fax and other communications devices to initiate and receive VoIP calls over a network. Call us to learn more! - [G.165 Echo Canceller Software](https://vocal.com/echo-cancellation/g-165-lec-software/) - VOCAL’s G.165 Echo Canceller software is fully compliant with ITU G.165 and optimized for execution on ANSI C and leading DSP architectures. - [Acoustic Echo Cancellation (AEC) Software](https://vocal.com/echo-cancellation/aec-software/) - AEC software removes echo created by an enclosed loudspeaker from the microphone signal with rapid convergence, double talk detection & echo tail upto 256ms - [VoIP Echo Cancellation Software](https://vocal.com/echo-cancellation/echo-cancellation-software-in-voip-gateways/) - VOCAL's VoIP Echo Cancellation software removes echoes generated within the transmission path of Satellite, VoIP and long distance networks - [Digital Network Echo Cancellation Software](https://vocal.com/echo-cancellation/digital-network-echo-canceller/) - Digital Network Echo Canceller optimized for DSPs and ARM provides both line and network echo cancellation performance that exceeds ITU G.168 - [Acoustic Beamforming Software](https://vocal.com/beamforming-2/acoustic-beamforming/) - Acoustic beamforming improves the SNR of speech signals. Contact us for acoustic beamformer solutions optimized for DSP, ARM and other processors - [WebRTC Gateways](https://vocal.com/webrtc/webrtc-gateways/) - WebRTC Gateways may be used as intermediaries to establish sessions and conduct WebRTC communications between disparate end points. Call us today! - [WebRTC and VOIP Compatibility](https://vocal.com/webrtc/webrtc-and-voip-compatibility/) - WebRTC and VoIP compatibility allows peers to communicate directly. Call to discuss your WebRTC and VoIP communication requirements - [WebRTC and Complete Call Security](https://vocal.com/webrtc/webrtc-and-complete-call-security/) - WebRTC uses fingerprints and certificates to ensure complete call security. Call to discuss your WebRTC application security requirements - [Overview of the JavaScript API for WebRTC](https://vocal.com/webrtc/overview-of-the-javascript-api-for-webrtc/) - Application developers that require support for WebRTC on web browsers can use a JavaScript API to interface with the WebRTC protocols. - [Overview of ICE for WebRTC](https://vocal.com/webrtc/overview-of-ice-for-webrtc/) - WebRTC is a suite of protocols that work together. One of the protocols used by WebRTC is the Interactive Connectivity Establishment protocol (ICE). - [How do I send WebRTC objects through a WebSocket?](https://vocal.com/webrtc/send-webrtc-objects-through-a-websocket/) - The WebRTC protocol assumes that a signaling link is available between the two endpoints of a streaming media session before the session starts. - [Establishing a WebRTC Media Session](https://vocal.com/webrtc/establishing-a-webrtc-media-session/) - Signaling protocols and JavaScript are used to establish WebRTC Media Sessions. Call to discuss your web real-time communication requirements! - [Embedded WebRTC for IoT Applications](https://vocal.com/webrtc/embedded-webrtc-for-iot-applications/) - WebRTC is a real-time communication protocol that is widely used by internet browsers. Browsers that support WebRTC are able to use a java script API to ... - [V2oIP Module](https://vocal.com/v2oip/v2oip-module/) - VOCAL's V2oIP suite includes network stack and transport layer, telephony and modem software, a range of audio video codecs, and SRTP and SSL - [V2oIP Suite](https://vocal.com/v2oip/v2oip-suite/) - Our V2oIP suite includes Network and SIP Stacks, a wide range of audio/video codecs, and encryption for secure communications. Call us to learn more! - [T.38 Image Extraction from Captured Network Data](https://vocal.com/voip/t-38-image-extraction-from-captured-network-data/) - Fax image extraction from T.38 Fax over IP data streams and recorded files. Call to discuss your fax lawful intercept requirements - [Voice over IP Adapters (ATA)](https://vocal.com/voip/voice-over-ip-adapters-ata/) - Our VoIP adapters (ATA) enable interoperability between analog/legacy terminals and modern terminals over packet and TDM networks. Contact us to learn more! - [RTP over QUIC (RoQ)](https://vocal.com/voip/quic/rtp-over-quic-roq/) - RTP over QUIC (RoQ) is a mapping of Real-Time Transport Protocol (RTP) to QUIC. RoQ allows for a secure encapsulation of RTP packets for transmission over QUIC. - [Mobile Voice over IP Technology](https://vocal.com/voip/mobile-voice-over-ip-technology/) - Our Mobile VoIP (mVoIP) solutions enable cell phones and other mobile devices to initiate and receive VoIP calls. Call us to learn more! - [IPv6 - Internet Protocol Version 6](https://vocal.com/networking/ipv6/) - IPv6 is the latest iteration of the Internet Protocol (IP). It was developed by the Internet Engineering Task Force and reached draft standard status in 1998. - [T.30-E Color Fax Software](https://vocal.com/fax-modem/t-30-e-color-fax/) - T.30-E Color Fax software optimized for DSPs and ARM provides Group 3 facsimile control to transmit JPEG color and gray scale faxes ... - [Detection of Synthesized Speech Spoofing Attacks](https://vocal.com/speech-processing-and-audio/detection-of-synthesized-speech-spoofing-attacks/) - The ability to detect synthesized speech is an important application in Automatic Speaker Verification (ASV) systems. Modern deepfake audio is able to ... - [Detection of ASV Replay Spoofing Attacks](https://vocal.com/speech-processing-and-audio/detection-of-asv-replay-spoofing-attacks/) - Replay attacks of Automatic Speaker Verification (ASV) occur when the audio of an authorized user is covertly recorded, and is played back by an impostor - [Comb Filtering for Speech Enhancement](https://vocal.com/speech-processing-and-audio/comb-filtering-for-speech-enhancement/) - Comb filter is a filter with multiple pass and stop bands. In acoustics, comb filtering is used to described the phenomena when two sound waves collide. - [Binaural Masking](https://vocal.com/speech-processing-and-audio/binaural-masking/) - Binaural masking cab be applied to speech. When in a noisy environment, the auditory system benefits from the separation of speech and noise. - [PSQM, PSQM+ & Perceptual Scale](https://vocal.com/speech-coders/perceptual-speech-quality-measure-psqm/) - PSQM algorithm objectively evaluates and quantifies on a perceptual scale the voice quality of voice-band (300Hz - 3400 Hz) speech codecs. - [Speech Codecs and Associated PSQM Values](https://vocal.com/speech-coders/associated-psqm-values/) - PSQM values for speech codecs G.711, G.726, G.729a, G.723.1, iLBC , GSM AMR and Speex tested with various speech files and network loads - [VOCAL Technologies Reference Designs](https://vocal.com/resources/reference-designs/) - Our Reference Designs for voice, video, data, and fax communications are used in radio, mobile and network VoIP and legacy modem applications. Call us today! - [iOS VoIP SDK](https://vocal.com/voip/ios-voip-sdk/) - iOS VoIP SDK library speeds iPhone/iPad app development with SIP stack, adaptive jitter, WB audio, echo & noise control solutions optimized for ARM & DSPs - [VoIP Effects on Data Modem Communications](https://vocal.com/voip/voip-effects-on-data-modem-communications/) - It is important to utilize high quality telecom providers and communications equipment when operating modem calls over VoIP networks. - [Hadamard Transform Digital Watermarking](https://vocal.com/video/hadamard-transform-digital-watermarking/) - Hadamard transform is used only in the real domain with values ±1 and does not require multiplications. Call to learn more about digital watermarking! - [UAV VoIP Gateway](https://vocal.com/voip/uav-voip-gateway/) - VOCAL's UAV VoIP Gateway solution enables unmanned aerial vehicle audio, video and radio communications over IP networks using VoIP protocols. - [Transparent Data Modem Relay for Legacy Applications](https://vocal.com/voip/transparent-data-modem-relay-for-legacy-applications/) - SIP Analog Data Modem Server for data center, VM or Cloud, combined with VOCAL's Analog Modem Adapter for a complete end to end solution. - [SIP Software Modem](https://vocal.com/voip/sip-software-modem/) - VOCAL's SIP Software Modem V.MoIP solution for dialup networking services implements an analog modem using SIP/VoIP protocols. - [SIP Analog Modem Server – Telocator Alphanumeric Protocol Gateway](https://vocal.com/voip/sams-telocator-alphanumeric-protocol/) - The SAMS Telocator Alphanumeric Protocol (TAP) Gateway combines modem software and TAP v1.8 to provide a solution for alphanumeric messaging applications. - [SIP Analog Modem Server for Facsimile (SAMS-F)](https://vocal.com/voip/sip-analog-modem-server-sams-f/) - The VOCAL SAMS for Facsimile (SAMS-F) is a solution for interoperating with legacy fax modems without the need for modem banks with E1/T1/ISDN connections. - [SIP Analog Modem Server - Modem as a Service (SAMS-MAAS)](https://vocal.com/voip/sip-analog-modem-server-modem-as-a-service/) - Modem as a Service (MaaS) is a solution for high volume users and can be especially attractive when customers have low volume use where a premium is placed on availability - [V.92 Modem-on-Hold, PCM upstream and Quick Connect Features](https://vocal.com/data-modem/v-92-pcmu-moh-qc/) - V.92 Modem Software optimized for DSPs provides Modem-On-Hold, Quick-connect, and PCM Upstream for usability and performance - [V.92 Modem Software](https://vocal.com/data-modem/v-92/) - V.92 modem software implements ITU V.92 which refers to procedures between a digital and an analog modem. Contact VOCAL for more information. - [V.91 Modem Software](https://vocal.com/data-modem/v-91/) - VOCAL’s V.91 software optimized for DSPs supports a duplex digital modem for use on 4-wire circuits at rates up to 64kbps - [V.90 Modem Software](https://vocal.com/data-modem/v-90/) - V.90 modem software implements ITU V.90 Recommendation which defines procedures between a “digital” and an “analog” modem. - [V.44 Data Compression Software](https://vocal.com/data-modem/v-44-data-compression/) - VOCAL's V.44 data compression software optimized for DSPs provides a lossless procedure for use with V-series data circuit-terminating equipment (DCEs) - [V.42 / V.42bis Software](https://vocal.com/data-modem/v-42/) - VOCAL's data modem software optimized for leading DSPs supports V.42, V.42bis, MNP2-4, MNP5, and MNP10 error correction protocols - [V.34 Modem Software](https://vocal.com/data-modem/v-34-modem-software/) - V.34 Modem Software supports real-time multi-channel high speed communications. Contact us for V.34 solutions optimized for leading DSP, ARM & other processors - [V.32bis and V.32 Modem Software](https://vocal.com/data-modem/v-32/) - VOCAL's V.32bis / V.32 modem software optimized for leading DSP and RISC/CISC processors is available as a library or complete design - [V.22bis / V.22 / Bell 212 / V.23 / V.21 / Bell 103 Modem Software](https://vocal.com/data-modem/v-22/) - VOCAL's V.22bis V.22 Bell 212 V.23 V.21 and Bell 103 Software library supports multiple modulations on a single DSP - [Command Set Controller Software](https://vocal.com/data-modem/command-set-controller/) - VOCAL's Command Set Controller (CSC) software provides industry standard fax/facsimile and data modem controls optimized for leading DSPs - [56K Modem Software](https://vocal.com/data-modem/56k-modem/) - VOCALs 56k modem software supports analog and digital modes of operation. Contact us for 56K modem solutions optimized for leading DSP, ARM and other processors - [SIP Registration](https://vocal.com/sip/registration/) - SIP Registration is where the SIP register method creates bindings between AORs and the contact addresses where a user can be reached. - [SIP User Authentication](https://vocal.com/sip/sip-user-authentication/) - There are two forms of SIP User Authentication - authentication of a user agent (UA) by a proxy, redirect, or registration server; and authentication of one UA by another. - [Voice Activity Detection (VAD) Software](https://vocal.com/voice-quality-enhancement/vad/) - VAD software reduces speech coder bit rates & supports echo cancellation, noise reduction & AGC. Contact us for custom voice solutions optimized for DSPs & ARM - [Advanced Encryption Standard (AES) IP Core](https://vocal.com/hardware-reference-designs/advanced-encryption-standard-aes-ip-core/) - VOCAL's AES IP Core firmware supports 128, 192, and 256 key lengths and is optimized for leading DSPs and RISC, CISC processors - [T.38 Transmission Over SRTP](https://vocal.com/voip/t-38-over-srtp/) - VOCAL's SRTP software library provides increased security for fax transmissions using T.38 FoIP protocol. - [Encryption](https://vocal.com/cryptography/encryption/) - VOCAL's wide range of optimized cryptographic solutions are available in both hardware and software formats. - [TSVCIS Interoperability Features](https://vocal.com/speech-coders/tsvcis-melpe/tsvcis-interoperability-features/) - Tactical Secure Voice Cryptographic Interoperability Specification (TSVCIS) uses a layered bitstream for interoperability between waveforms and voice modes. - [AES GCM Encryption Algorithms](https://vocal.com/cryptography/gcm-and-gmac-authenticated-encryption-algorithms/) - AES GCM, or Galois Counter Mode, encryption algorithms detect both accidental modifications and intentional, unauthorized modifications of protected data. - [SDES](https://vocal.com/secure-communication/sdes/) - The SDES Description for Media Streams defines a mechanism to negotiate the cryptographic parameters necessary for the Secure Real-time Transport Protocol - [Speech Enhancement Utilizing a Bone Conduction Microphone](https://vocal.com/voice-quality-enhancement/utilizing-a-bone-conduction-microphone/) - Utilizing multiple air-conduction microphones with a bone conduction microphones combines the best of both worlds. - [Space Application Development Board](https://vocal.com/system-designs/space-application-development-board/) - The SADB-C6727B enables developers to implement communications and i/o systems for space vehicles/spacecraft on hardware similar to the final rad-hard designs - [Space Application Development Board for Full Duplex Voice Comms](https://vocal.com/system-designs/space-application-development-board-for-full-duplex-hands-free-voice-communication-systems/) - Enables developers to implement algorithms for full-duplex hands-free comms systems on hardware similar to that deployed for spacecraft in a rad-hard design. - [Lawful Interception Solutions](https://vocal.com/contact-us/lawful-interception-solutions/) - Hardware and software designs for VoIP, voice, video, fax and data communications. Call to discuss your Lawful Interception requirements. - [How Do I Transfer MPEG2 Video in an RTP Stream?](https://vocal.com/resources/development/how-do-i-transfer-mpeg2-video-in-an-rtp-stream/) - A TCP client is a program that connects to a TCP server, the client initiates the connection and the server receives connection requests. - [Why modems fail with traditional Analog Telephone Adaptors](https://vocal.com/voip/why-modems-fail-with-traditional-analog-telephone-adaptors/) - [ITU H.264](https://vocal.com/video-codecs/itu-h-264/) - H.264 video compression is used in video conferencing, video surveillance and video streaming. Call to discuss your video application requirements - [1800# Toll Free Data Service SAMS Supported Back End](https://vocal.com/1800-toll-free-data-service-sip-analog-modem-server-sams-supported-back-end/) - Network providers and carriers offer enterprise customers ability to deliver toll free services. These 1-800 phone numbers connect customers to talk toll free - [How Can I Parse an Integer from a String in C Code?](https://vocal.com/resources/development/how-can-i-parse-an-integer-from-a-string-in-c-code/) - There are standard C functions that can parse an integer from a string such as atol or sscanf. The following example is a parsing function built from scratch. - [What is JSON?](https://vocal.com/resources/development/what-is-json/) - Components of the signal with frequencies less than the cutoff are let through unaffected, while components with higher frequencies are completely removed. - [Codecs Used in Voice over IP Technologies](https://vocal.com/voip/codecs-used-in-voice-over-ip-technologies/) - VoIP waveform codecs can be used with both audio and speech whereas model based codecs are better for speech production. Call us to learn more! - [What Is a Sinc Filter?](https://vocal.com/resources/development/what-is-a-sinc-filter/) - Components of the signal with frequencies less than the cutoff are let through unaffected, while components with higher frequencies are completely removed. - [How Can I Start a Win32 Thread using C?](https://vocal.com/resources/development/how-can-i-start-a-win32-thread-using-c/) - Starting a Windows Thread using C can be done using the Win32 CreateThread function. - [How Can I Start a Linux Thread using C?](https://vocal.com/resources/development/how-can-i-start-a-linux-thread-using-c/) - Starting a Linux Thread using C can be done using the create_thread function from the pthread library. - [How Can I Implement Audio Sample Rate Conversion?](https://vocal.com/resources/development/how-can-i-implement-audio-sample-rate-conversion/) - When doing an audio sample rate conversion, the sample rate can be increased (adding new samples) or decreased (removing samples). - [How Can I Find the Latest Version of a File Using a Linux Shell Script?](https://vocal.com/resources/development/how-can-i-find-the-latest-version-of-a-file-using-a-linux-shell-script/) - With this command, the most recently modified file will appear first on the list, so the ‘head’ command will print only the most recently modified file. - [Caller ID](https://vocal.com/caller-id/) - VOCALs Caller ID software can be used to generate and detect Calling Identity Delivery. The CID software is compliant with ETSI ES 200 778-1 & ETSI ES 200 778-2 - [How Can I Extract Image Data from a TIFF File?](https://vocal.com/resources/development/how-can-i-extract-image-data-from-a-tiff-file/) - The LibTIFF API can be used to write a program to extract data from a TIFF file - [What is alsamixer?](https://vocal.com/resources/development/what-is-alsamixer/) - Alsamixer is a program for controlling ALSA sound cards. It is included in many Linux distributions, and can be run by typing ‘alsamixer’ on the command line. - [How Can I Use Zip Archives on the Command Line?](https://vocal.com/resources/development/how-can-i-use-zip-archives-on-the-command-line/) - Compressing and decompressing zip archives on the command line requires a command line program that can use zip archives, like: ‘zip’, ‘unzip’ and ‘7-Zip’. - [How Can I Use a Pre-Built Native Shared Object Library in an Android Studio Application?](https://vocal.com/resources/development/how-can-i-use-a-pre-built-native-shared-object-library-in-an-android-studio-application/) - This article will illustrate the process with an example application, which will use the nodejs-mobile library which can be downloaded pre-built for Android. - [How Can I Get the Local Address for Incoming UDP Packets in Windows?](https://vocal.com/resources/development/how-can-i-get-the-local-address-for-incoming-udp-packets-in-windows/) - The function recv_localaddr shows how to use recvmsg to get the local address of a packet. - [How Can I Get the Local Address for Incoming UDP Packets in Linux?](https://vocal.com/resources/development/how-can-i-get-the-local-address-for-incoming-udp-packets-in-linux/) - The function recv_localaddr shows how to use recvmsg to get the local address of a packet. - [How Can I Analyze the Stability of a Physics-Based Discreet Time-Step Simulation?](https://vocal.com/resources/development/how-can-i-analyze-the-stability-of-a-physics-based-discreet-time-step-simulation/) - To send Multicast Packets, create a UDP socket and use the sendto function with a multicast address. - [How Can I Send Multicast Packets Using the Berkeley Sockets API?](https://vocal.com/resources/development/how-can-i-send-multicast-packets-using-the-berkeley-sockets-api/) - To send Multicast Packets, create a UDP socket and use the sendto function with a multicast address. - [How Can I Receive Multicast Packets Using the Berkeley Sockets API?](https://vocal.com/resources/development/how-can-i-receive-multicast-packets-using-the-berkeley-sockets-api/) - Multicast packets can be received by UDP sockets that are bound to an unspecified address, the receiving computer must subscribe to the multicast address. - [What Is Fixed-Point Math?](https://vocal.com/resources/development/what-is-fixed-point-math/) - Fixed-point math is a way to represent fractional values using integers by selecting a constant scaling factor that is implicitly applied to every value. - [How Does Branching and Decision-Making Work in Perl?](https://vocal.com/resources/development/how-does-branching-and-decision-making-work-in-perl/) - The Perl language includes a number of ways to implement branching, choosing a method is a matter of preference. - [How Do I Use Apple CallKit in Xamarin?](https://vocal.com/resources/development/how-do-i-use-apple-callkit-in-xamarin/) - Apple CallKit is an API that lets applications implement the same user interface for calling that other iOS phone apps use. - [How Can I Write a Windows Batch Script that Can Be Run from Any Folder?](https://vocal.com/resources/development/windows-batch-script-that-can-be-run-from-any-folder/) - Any Windows batch script can be run from any folder by specifying a relative path to the script on the command line. - [How Can I Find the Latest Version of a File Using a Windows Batch Script?](https://vocal.com/resources/development/find-the-latest-version-of-a-file-using-a-windows-batch-script/) - With this command, the file with the most recent write time will be printed last, and end up as the value of recent_file. - [How Can I Control GPIOs on Embedded Linux from Python?](https://vocal.com/resources/development/how-can-i-control-gpios-on-embedded-linux-from-python/) - To control GPIOs from Python requires running the correct Linux system calls from Python code. - [How Does Acoustic Imaging Work?](https://vocal.com/resources/development/what-is-acoustic-imaging/how-does-acoustic-imaging-work/) - Acoustic Imaging utilizes the technology of Microphone Array Beamforming, in which sound sources propagate as a plane wave to an array of N microphones. - [What is Acoustic Imaging?](https://vocal.com/resources/development/what-is-acoustic-imaging/) - Acoustic Imaging is a solution to visualize the location of sound sources, with the main application being noise source localization. - [Voice Quality Enhancement for Radio Communications](https://vocal.com/voice-quality-enhancement/voice-quality-enhancement-for-radio-communications/) - Voice Quality Enhancement (VQE) software is a critical component to a radio design to ensure the message of the radio operator is understood correctly. - [DNNs Optimize Beamforming Weights](https://vocal.com/beamforming-2/dnns-optimize-beamforming-weights/) - Deep Neural Networks can either clean up the multi-microphone inputs prior to beamforming or by post-processing the beamforming output. - [Physical Layer Security for Cognitive Radio Networks](https://vocal.com/beamforming-2/physical-layer-security-for-cognitive-radio-networks/) - By utilizing multi-antenna systems, the beampatterns of the antennas can be shaped to prevent users from interfering with the QoS of Cognitive Radio Networks. - [Speech as a Biomarker](https://vocal.com/voice-processing/speech-as-a-biomarker/) - Speech as a biomarker cant help us understand a persons physical and mental state. - [G.729 Annex D](https://vocal.com/speech-coders/g-729-annex-d/) - G.729 Annex D encodes a 10ms (80 sample) frame into 64 bits, while G.729 (and G.729 Annex A) encodes a frame into 80 bits. - [Distributed Multi-Mic Speech Enhancement](https://vocal.com/beamforming-2/distributed-multi-mic-speech-enhancement/) - Multi-mic noise reduction software is a signal enhancement algorithm that combines information from multiple microphones to improve the signal to noise ratio. - [Rotating Arrays for Wideband Beamforming](https://vocal.com/beamforming-2/rotating-arrays-for-wideband-beamforming/) - Rotating arrays for wideband beamforming are a potential solution to the frequency variant beamwidth problem. - [How Do I Use the Analog Inputs on the AM335x Processor?](https://vocal.com/resources/development/how-do-i-use-the-analog-inputs-on-the-am335x-processor/) - The analog inputs on the AM335x processor are supported by the Linux kernel, so using Linux is one way to use them. - [How Can I Write A Linux Shell Script That Can Be Run From Any Folder?](https://vocal.com/resources/development/how-can-i-write-a-linux-shell-script-that-can-be-run-from-any-folder/) - Any linux shell script can be run from any folder by specifying a relative path to the script on the command line. - [How Can I Use an ALSA Device from Multiple Processes?](https://vocal.com/resources/development/how-can-i-use-an-alsa-device-from-multiple-processes/) - The ALSA dmix plugin creates an alias for the device which works like a new ALSA device. - [How Can I Find Files on the Linux Command Line?](https://vocal.com/resources/development/how-can-i-find-files-on-the-linux-command-line/) - The linux find command searches recursively by default (it will enter sub-directories) and considers every file it comes across. - [Voice Quality Enhancement for Robots](https://vocal.com/voice-quality-enhancement/voice-quality-enhancement-for-robots/) - Voice Quality Enhancement (VQE) is an important software component in robotic applications which have an audio-based human / machine interface - [DNN for Beamforming Preprocessing](https://vocal.com/beamforming-2/dnn-for-beamforming-preprocessing/) - If a DNN algorithm removes uncorrelated noise from each channel, then the beamforming preprocessing system will achieve greater SNR improvements. - [Beamforming Post-filters using DNNs](https://vocal.com/beamforming-2/beamforming-post-filters-using-dnns/) - Beamforming post-filters are used because uncorrelated noise and estimation errors of the direction of arrival degrades the performance of beamformers. - [The Missing Security Layer](https://vocal.com/secure-communication/the-missing-security-layer/) - All layers in the IP stack have established security and cryptography schemes except one, the Physical (PHY) layer. - [The Importance of Physical Layer Security in Emerging Networks](https://vocal.com/secure-communication/physical-layer-security-in-emerging-networks/) - Physical Layer Security (PLS) is important for protecting the information shared between devices on 5G and next generation networks. - [Maximum Ratio Combining](https://vocal.com/beamforming-2/maximum-ratio-combining/) - Maximum Ratio Combining (MRC) is an optimization technique for combining signals that are carrying the same information. - [What is Pin Multiplexing on Embedded Processors?](https://vocal.com/resources/development/what-is-pin-multiplexing-on-embedded-processors/) - Pin Multiplexing allows embedded processors to have physical pins that are configurable with different functions. - [How Can I Write Directly to the Console from the Linux Kernel?](https://vocal.com/resources/development/how-can-i-write-directly-to-the-console-from-the-linux-kernel/) - In order to Write Directly to the Console from the Linux Kernel, one way is to use the kernel function get_current_tty(). - [How Can I Parse Data to a Hash of Arrays in Perl?](https://vocal.com/resources/development/how-can-i-parse-data-to-a-hash-of-arrays-in-perl/) - To parse data to a hash of arrays, the data must be in a format that Perl can read. One format that will work is a text file separated into lines. - [How Can I Marshal an Array of Structures from C# to Native Code?](https://vocal.com/resources/development/how-can-i-marshal-an-array-of-structures-from-c-to-native-code/) - To marshal an array, one can use the C# Marshal function StructureToPtr in a loop. - [How Can I Call Shared Library Functions from C# in Linux?](https://vocal.com/resources/development/how-can-i-call-shared-library-functions-from-c-in-linux/) - Calling shared library functions can be done by declaring the functions in C# using the DllImport attribute. - [How Can I Build a C# Application for an Embedded ARM Processor?](https://vocal.com/resources/development/how-can-i-build-a-cs-application-for-an-embedded-arm-processor/) - Build a C# application with the .NET SDK from Microsoft, the SDK is available for download for a few different platforms, including ARM and x64. - [Wearable Devices Utilize Voice Quality Enhancement](https://vocal.com/voice-quality-enhancement/wearable-devices-utilize-voice-quality-enhancement/) - Wearable devices such as, smart watches and fall assist devices, need to include Voice Quality Enhancement software as part of the product design. - [Voice Quality Enhancement for Smart Speakers](https://vocal.com/voice-quality-enhancement/voice-quality-enhancement-for-smart-speakers-2/) - To overcome acoustic challenges, Voice Quality Enhancement (VQE) software is a core component to every smart speaker device. - [Automatic Echo Delay Compensation for AEC](https://vocal.com/echo-cancellation/automatic-echo-delay-compensation-for-aec/) - automatic echo delay algorithm estimates the echo delay observed between the loudspeaker and microphone, and automatically adjusts the delay compensation. - [5G](https://vocal.com/5g/) - 5G is a significant step beyond 4G LTE networks in multiple aspects. 5G was defined to reduce latency, increase bandwidth, and increase reliability. - [Echo Cancellation: Cross Spectral Residual Echo Suppression](https://vocal.com/echo-cancellation/cross-spectral-residual-echo-suppression/) - Residual Echo Suppression is necessary component of an Acoustic Echo Cancellation (AEC) solution. - [Convergence and Divergence Check for Cross Spectral Residual Echo Suppression](https://vocal.com/echo-cancellation/convergence-and-divergence-check-for-cross-spectral-residual-echo-suppression/) - Cross Spectral Residual Echo Suppression implemented in the frequency domain for Nonlinear Processing of residual echoes needs additional control logic. - [What is Hybrid Beamforming?](https://vocal.com/beamforming-2/what-is-hybrid-beamforming/) - Hybrid beamforming is the combination of features in RF communication channels from analog and digital beamforming. - [Reconfigurable Intelligent Surfaces in Covert Communications](https://vocal.com/beamforming-2/reconfigurable-intelligent-surfaces-in-covert-communications/) - Reconfigurable Intelligent Surfaces (RIS), are meta-surfaces that alter the electromagnetic wave properties of the signal impinging the surface. - [mmWave Beamforming in Covert Communications](https://vocal.com/beamforming-2/mmwave-beamforming-in-covert-communications/) - mmWave Beamforming for communications has been of interest for 5G and 6G researchers because of the ultra-wide bandwidth. - [How Can I Run an Interactive Program from a Linux Shell Script?](https://vocal.com/resources/development/linux-shell-script-run-an-interactive-program/) - To Run an Interactive Program from a Linux Shell Script, two ways to do this are using pipes and using here documents. - [How Can I Implement a Configuration File for a Perl Script?](https://vocal.com/resources/development/how-can-i-implement-a-configuration-file-for-a-perl-script/) - Perl’s hash type is a good choice for storing a configuration database,with the keys as names of configuration variables. - [Sound Source Localization](https://vocal.com/beamforming-2/sound-source-localization/) - Sound Source Localization serves as the front-end to acoustic beamforming by steering the beam to the desired sound source. - [Multi-Band Dynamic Range Compression (DRC) Software](https://vocal.com/voice-quality-enhancement/multi-band-dynamic-range-compression-software/) - Dynamic Range Compression (DRC) is a useful signal processing tool for both playback and capture audio. DRC is often implemented after Automatic Gain Control. - [Parametric Equalization (EQ) Filtering Software](https://vocal.com/voice-quality-enhancement/parametric-equalization-filtering-software/) - Parametric EQ filters provides user/implementor with the ability to shape the audio signal to meet their design requirements or preference for quality. - [Bluetooth Headset Voice Processing Software](https://vocal.com/voice-processing/bluetooth-headset-voice-processing-software/) - Bluetooth Headsets require a collection of voice processing software modules, in order to achieve the best audio quality experience. - [Voice Quality Enhancement for Conference Room Speakerphones](https://vocal.com/voice-quality-enhancement/voice-quality-enhancement-for-conference-room-speakerphones/) - Voice Quality Enhancement (VQE) software is a necessary component in the design of Large Room Conference Speakerphones. - [What Are the Components of a Video Conferencing Device?](https://vocal.com/resources/development/what-are-the-components-of-a-video-conferencing-device/) - Devices that support video conferencing require an image sensor for video input, a display for video output, a microphone for input and a speaker for output. - [How Should I Fill Out the Payload Type Field of an RTP Packet?](https://vocal.com/resources/development/how-should-i-fill-out-the-payload-type-field-of-an-rtp-packet/) - The RTP payload type is an arbitrary number that identifies which media codec was used to generate the payload data. - [How do I use padding in RTP packets?](https://vocal.com/resources/development/how-do-i-use-padding-in-rtp-packets/) - Padding is the addition of extra bytes at the end of an RTP packet that do not contribute to the packet’s payload data. - [How can I Search for C Function Calls Using Perl?](https://vocal.com/resources/development/how-can-i-search-for-c-function-calls-using-perl/) - The Perl code (cfsearch.prl) first defines a list of C functions to search for. To keep the list simple, the word ‘arg’ is used in place of actual arguments. - [How Can I Parse Command Line Arguments in Perl?](https://vocal.com/resources/development/how-can-i-parse-command-line-arguments-in-perl/) - Perl passes command line arguments to a script using the built-in @ARGV array. This variable does not need to be declared. - [How can I Iterate Files in a Folder Tree Using Perl?](https://vocal.com/resources/development/how-can-i-iterate-files-in-a-folder-tree-using-perl/) - Perl has built-in functions that can be used for this. The functions are ‘opendir’, ‘readdir’ and ‘closedir’. - [How can I generate URIs for SIP messages?](https://vocal.com/resources/development/how-can-i-generate-uris-for-sip-messages/) - The syntax for SIP Universal Resource Identifiers (URIs) is described in the SIP RFC (RFC 3261). SIP URIs follow the more general conventions of URIs described in RFC 2396. - [How can I control the bitrate of an H.264 stream?](https://vocal.com/resources/development/how-can-i-control-the-bitrate-of-an-h-264-stream/) - There are many different implementations of H.264 running on a variety of platforms that allow varying levels of control over the bitrate. - [How can I control the audio route for Bluetooth in an Android or iOS application?](https://vocal.com/resources/development/how-can-i-control-the-audio-route-for-bluetooth-in-an-android-or-ios-application/) - The Android or iOS operating system will do this for you. There is a misconception that mobile applications should have a “Bluetooth button”. - [3DES - Triple Data Encryption Standard (Triple-DES)](https://vocal.com/cryptography/tdes/) - VOCAL's hardware and software cryptographic solutions include Triple DES Encryption (3DES) with a longer key for improved security over DES. - [Battlefield VOX Software](https://vocal.com/voice-quality-enhancement/battlefield-voice-activated-transmission-vox/) - VOCAL's Battlefield VOX software superior voice detection rejects spurious signals in noisy environments. Contact us for VOX solutions optimized for DSPs & ARM - [Audio Ducking](https://vocal.com/audio/audio-ducking/) - What is Audio Ducking? Audio ducking is a common audio effect applied to music performances or recordings. Call to learn more about our audio ducking solutions. - [Multi-Mic Noise Reduction Software](https://vocal.com/noise-reduction/multi-mic-noise-reduction-software/) - Multi-mic noise reduction software is a signal enhancement algorithm that utilizes information from multiple microphones to determine the optimal noise filter. - [PESQ for AEC Evaluation](https://vocal.com/echo-cancellation/pesq-for-aec-evaluation/) - PESQ (Perceptual Evaluation of Speech Quality) is an objective test measure established by the ITU-T P.862. - [What is SEI Cert C?](https://vocal.com/resources/development/what-is-sei-cert-c/) - SEI Cert C is a secure coding standard for the C programming language; to avoid software vulnerabilities in safety critical systems. - [Acoustic Echo Cancellation](https://vocal.com/echo-cancellation/acoustic-echo-canceller/) - VOCAL’s Robust Acoustic Echo Cancellation (AEC) software is an efficient, portable, customizable full-duplex Acoustic Echo Canceller solution - [Voice Quality Enhancement for TWS Earbuds](https://vocal.com/voice-quality-enhancement/voice-quality-enhancement-for-tws-earbuds/) - Voice Quality Enhancement (VQE) software is a critical component in the design of True Wireless Stereo (TWS) earbuds. - [Musical Noise Mitigation in Nonlinear Processing of Echo](https://vocal.com/echo-cancellation/musical-noise-mitigation-in-nonlinear-processing-of-echo/) - Musical noise is heard when there are isolated peaks in the time-frequency spectrum of an audio signal. - [What is Modified Condition / Decision Coverage?](https://vocal.com/resources/development/what-is-modified-condition-decision-coverage/) - Modified Condition / Decision Coverage (MC/DC) is used in the development and testing of safety-critical software. - [What is Cyclomatic Complexity?](https://vocal.com/resources/development/what-is-cyclomatic-complexity/) - Cyclomatic Complexity is a software quality metric used to indicate the number linearly independent paths in a function. - [Stereo Acoustic Echo Cancellation for Conferencing](https://vocal.com/echo-cancellation/stereo-acoustic-echo-cancellation-for-conferencing/) - Echo Cancellation for conferencing software is required for applications which can mix independent audio streams for the left and right loudspeakers. - [How can I build a firmware image for the Beaglebone PRU?](https://vocal.com/resources/development/how-can-i-build-a-firmware-image-for-the-beaglebone-pru/) - PRU firmware can be written in C or assembly. Firmware written in C can be compiled by the TI ‘clpru’ compiler which is part of the ‘ti-cgt-pru’ package. - [What T.38 Parameters can be in SDP?](https://vocal.com/resources/development/what-t-38-parameters-can-be-in-sdp/) - T.38 parameters are encoded in SDP within media sections using the ‘image’ media type as described in RFC-6466. - [What is SIP?](https://vocal.com/resources/development/what-is-sip/) - The Session Initiation Protocol (SIP) is a signaling protocol that specifies syntax and transfer procedures of messages that are meant to establish sessions. - [What is SDP?](https://vocal.com/resources/development/what-is-sdp/) - The Session Description Protocol (SDP) specifies the syntax for messages that describe media sessions running on IP networks. - [How can I use watchdog hardware in Linux?](https://vocal.com/resources/development/how-can-i-use-watchdog-hardware-in-linux/) - The standard Linux watchdog drivers create a device node (/dev/watchdog) which is used to control the watchdog hardware. - [How can I control text file line endings using Perl?](https://vocal.com/resources/development/how-can-i-control-text-file-line-endings-using-perl/) - In Perl, binary files are read in fixed sized blocks. This example reads the input file in blocks, and appends each block to the end of a variable. - [Advantages of VOCAL’s AEC Software: Unusual Echo Response Handling](https://vocal.com/echo-cancellation/vocals-aec-software-unusual-echo-response-handling/) - VOCAL’s AEC software has many advantages over open source AEC solutions, like being able to handle unusual echo path responses. - [Advantages of VOCAL’s AEC Software: True Fullband Audio Support](https://vocal.com/echo-cancellation/vocals-aec-software-true-fullband-audio-support/) - VOCAL’s AEC software has many advantages over open source AEC solutions, like being able to perform AEC at fullband sampling rates. - [What is Statement Code Coverage?](https://vocal.com/resources/development/what-is-statement-code-coverage/) - Statement Code Coverage is the number of the code statements executed over the total number of code statements for the executable under test. - [Why is Shifting Necessary in Fixed Point FFTs?](https://vocal.com/resources/development/why-is-shifting-necessary-in-fixed-point-ffts/) - Shifting is necessary when performing fixed point FFTs due to the limited dynamic range of fixed point arithmetic. - [What is Logically Dead Code?](https://vocal.com/resources/development/what-is-logically-dead-code/) - Logically dead code are branches of software that cannot be reached given the logical conditions. - [How to Optimize Fixed Point Frequency Domain Filter](https://vocal.com/resources/development/optimize-fixed-point-frequency-domain-filter/) - This example shows how to optimize Fixed Point Frequency Domain Filter (FIR Filter) - [Why are High Pass Filters Important in Audio Signal Processing?](https://vocal.com/audio/why-are-high-pass-filters-important-in-audio-signal-processing/) - High pass filters are not only important for improving the listening quality of a signal, but also for the signal processing that occurs on that signal. - [Audio Conferencing](https://vocal.com/audio/audio-conferencing/) - Audio Conferencing is the combination of multiple audio streams into a single stream for a given destination. - [What is the PRU co-processor on the Beaglebone?](https://vocal.com/resources/development/what-is-the-pru-co-processor-on-the-beaglebone/) - The Beaglebone AM3358 CPU includes two separate co-processors called Programmable Real-Time Units (PRU). - [How do I use the AM335x PRU with Linux?](https://vocal.com/resources/development/how-do-i-use-the-am335x-pru-with-linux/) - Running firmware on the AM335x PRU co-processors can be done using the Linux remoteproc drivers, which might require modifying the Linux configuration. - [How can I implement double-buffering in shared memory?](https://vocal.com/resources/development/implement-double-buffering-in-shared-memory/) - Double-buffering is a simple way to move data from one processor to the other when they have access to the same region of memory. - [How do I make a TLS server connection using OpenSSL?](https://vocal.com/resources/development/how-do-i-make-a-tls-server-connection-using-openssl/) - One way to make a TLS server connection with OpenSSL is to use its SSL layer on top of a TCP connection made using the Berkeley sockets API. - [How do I make a TLS client connection using OpenSSL?](https://vocal.com/resources/development/how-do-i-make-a-tls-client-connection-using-openssl/) - One way to make a TLS client connection with OpenSSL is to use its SSL layer on top of a TCP connection made using the Berkeley sockets API. - [VPBX Home Gateway Design Features](https://vocal.com/ata-analog-telephone-adapter/vpbx-home-gateway-system-features/) - VOCAL's VPBX Home Gateway System reference design optimized for leading DSPs provides standard telephony features for VoIP applications - [What is Shift-Left Testing?](https://vocal.com/resources/development/what-is-shift-left-testing/) - Shift-Left Testing is the coding practice to test early in the software development life cycle. - [Early Reflections](https://vocal.com/dereverberation/early-reflections/) - VOCAL's Dereverberation algorithm removes early reflections (echoes) of the direct sound source arriving at a microphone about 30ms after the direct sound - [MUSIC (Multiple Signal Classification) Algorithm](https://vocal.com/beamforming-2/music-algorithm/) - MUSIC is a spatial spectrum estimation algorithm based on second order statistics. It attracted intensive studies due to the following perceived advantages. - [Voice Activity Detection for Dereverberation](https://vocal.com/dereverberation/voice-activity-detection/) - VOCAL's VAD algorithms use feature extraction, decision and decision smoothing with adaptive thresholds to reduce VAD errors and probability of false alarms - [Acoustic Beamforming with Microphone Array](https://vocal.com/beamforming-2/acoustic-beamforming-with-microphone-array/) - Acoustic beamforming can be calculated more simply using far-field model without losing significant accuracy. - [Fixed Point Mathematics for Acoustic Echo Cancellation](https://vocal.com/echo-cancellation/fixed-point/) - VOCAL's acoustic echo cancellation libraries use fixed point math for maximum performance and minimal power usage on leading DSPs - [Dereverberation using Spectral Subtraction](https://vocal.com/dereverberation/spectral-subtraction/) - VOCAL's Dereverberation algorithm uses spectral subtraction to remove the Room Impulse Response and enhance speech intelligibility - [Linear Array Beamforming](https://vocal.com/beamforming-2/linear-array-beamforming/) - By measuring the relative delays of the sound wave reaching each microphone, we can calculate the incoming angle of the sound wave. - [Stereophonic Acoustic Echo Cancellation](https://vocal.com/echo-cancellation/stereophonic/) - VOCAL's Acoustic Echo Cancellation software models the echo path in stereophonic systems for improved speech enhancement - [Microphone Array Beamforming](https://vocal.com/beamforming-2/microphone-array/) - VOCAL's Beamforming Microphone Algorithms for hands free systems uses a Microphone Array to enhance speech quality in noisy environments. - [Musical Noise in Acoustic Noise Reduction](https://vocal.com/noise-reduction/musical-noise/) - Acoustic Noise Reduction spectral subtraction algorithms use filtering to remove the isolated peaks that sound like musical tones to our ears - [Gunshot detection and localization](https://vocal.com/beamforming-2/gunshot-detection-and-localization/) - Autonomous detection of gunshots has gained traction as opposed to the reliance on A activated reports due to the non-timely reportage by human actors. - [Single Directionless Filter For Circular Array Sum & Filter Beamformer](https://vocal.com/beamforming-2/single-directionless-filter-for-circular-array-sum-and-filter-beamformer/) - Single Directionless Filter For Circular Array Sum and Filter Beamformer. Call to discuss your beamforming application requirements. - [What is a DTLS fingerprint?](https://vocal.com/resources/development/what-is-a-dtls-fingerprint/) - A DTLS fingerprint is a way for the two endpoints of a connection to verify each other’s identity even if self-signed certificates are used in the handshake. - [How do I make TLS certificates for testing?](https://vocal.com/resources/development/how-do-i-make-tls-certificates-for-testing/) - TLS certificates for testing can be made using the OpenSSL command line tool, which can be installed on most computers. - [How do I make a TCP server using the Berkeley sockets API?](https://vocal.com/resources/development/how-do-i-make-a-tcp-server/) - A TCP server program will first create a TCP socket and bind it to a local address and port. It will then listen for incoming client connections on that socket. - [How do I make a TCP client using the Berkeley sockets API?](https://vocal.com/resources/development/how-do-i-make-a-tcp-client/) - A TCP client is a program that connects to a TCP server, the client initiates the connection and the server receives connection requests. - [What is Multichannel AEC?](https://vocal.com/echo-cancellation/what-is-multichannel-aec/) - Multichannel AEC is an acoustic echo cancellation solution which interfaces with multiple loudspeakers and/or multiple microphone signals. - [How do I build a Linux device tree?](https://vocal.com/resources/development/how-do-i-build-a-linux-device-tree/) - Linux device tree binaries are built from source code using the device tree compiler. The source code usually has a ‘.dts‘ or ‘.dtsi’ extension. - [What is Buildroot?](https://vocal.com/resources/development/what-is-buildroot/) - Buildroot is a collection of scripts that simplify the process of generating an embedded Linux system from source code. - [What is the Linux menuconfig system?](https://vocal.com/resources/development/what-is-the-linux-menuconfig-system/) - The Linux menuconfig system is a way to select which parts of the Linux kernel will be built using a graphical interface with search capabilities. - [What is Loop Unrolling?](https://vocal.com/resources/development/what-is-loop-unrolling/) - Loop unrolling expands the content of a control loop, and in some cases eliminates the need of the control loop entirely. - [What is Inlining?](https://vocal.com/resources/development/what-is-inlining/) - Inlining embeds a function directly into the calling function. The goal of this technique is to minimize the execution time of a coded algorithm. - [IP Intercom Software](https://vocal.com/software-modules/voip-software/ip-intercom-software/) - This intercom software package can be used for any IP based communication application, such as door bells, call boxes, and emergency call stations. - [How do I control GPIOs in Linux?](https://vocal.com/resources/development/how-do-i-control-gpios-in-linux/) - Embedded systems running Linux can use the gpiod library to read and write hardware GPIO values. - [What is Linux device tree?](https://vocal.com/resources/development/what-is-linux-device-tree/) - The Linux device tree describes the hardware and peripherals that the kernel image will interact with as it runs. - [How can I re-use code in Linux shell scripts?](https://vocal.com/resources/development/how-can-i-re-use-code-in-linux-shell-scripts/) - One solution is to use the source command which allows one script to include code from another script - [Fax Reference Designs](https://vocal.com/resources/reference-designs/fax/) - Fax Reference Designs for fax communications for legacy and softmodem applications over PSTN, radio, mobile and IP networks. Contact us today! - [Dual Mic Voice Enhancement Solution for Hands-free Radio Applications](https://vocal.com/noise-reduction/dual-mic-voice-enhancement/) - The Dual Mic Voice Enhancement software package makes for a good solution for any low power voice communications and voice control application. - [How do I control indicator LEDs in embedded Linux systems?](https://vocal.com/resources/development/how-do-i-control-indicator-leds-in-embedded-linux-systems/) - Using GPIO drivers directly is one way to control indicator LEDs, but Linux has another software layer on top of its GPIO drivers specifically for indicator LEDs. - [How do I control an I2C bus from a Linux application?](https://vocal.com/resources/development/how-do-i-control-an-i2c-bus-from-a-linux-application/) - I2C operations on Linux systems are handled by the Linux kernel, and usually these operations are hidden from user space behind a kernel-level device driver. - [How do I use Linux initramfs?](https://vocal.com/resources/development/how-do-i-use-linux-initramfs/) - When using initramf, a filesystem image is embedded into the kernel image. - [How do I debug an embedded Linux program using GDB?](https://vocal.com/resources/development/how-do-i-debug-an-embedded-linux-program-using-gdb/) - The ‘gdbserver’ command allows remote debugging. It runs on the target device and attaches to the process to be debugged. - [How do I run a Linux shell script?](https://vocal.com/resources/development/how-do-i-run-a-linux-shell-script/) - A shell scripts are files that contains commands. When a shell script is run, the Linux shell reads the commands and interprets them as if they were typed. - [How do I return values from functions in Linux shell scripts?](https://vocal.com/resources/development/how-do-i-return-values-from-functions-in-linux-shell-scripts/) - Linux shell scripts do not have local variables; all variables are global. Because of this, a function can edit any variable and use it as a return value. - [How do I encode or decode video with the Android NDK?](https://vocal.com/resources/development/how-do-i-encode-or-decode-video-with-the-android-ndk/) - When developing video applications for Android, it is recommended to use the platform tools available for fast and reliable operation. - [What are H.264 NAL units?](https://vocal.com/video-codecs/itu-h-264/what-are-h-264-nal-units/) - The H.264 codec was designed with some knowledge of the network through the Network Abstraction Layer. - [What are the components of a SoC audio system?](https://vocal.com/audio/what-are-the-components-of-a-soc-audio-system/) - One way to implement audio on an embedded system is to use an audio system on a chip (SoC audio); in many contexts, the SoC chip is also called a codec. - [Overview of JNI for Android Applications](https://vocal.com/resources/development/overview-of-jni-for-android-applications/) - Sometimes it is necessary and/or desirable to have parts of an Android application written in a low-level language such as C. - [Overview of Linux System Building using Cross-Compiling](https://vocal.com/resources/development/overview-of-linux-system-building-using-cross-compiling/) - Cross-compiling is the process of building software for a specific device running a certain CPU architecture on a different machine. - [Setting the Time on an Embedded Linux Device using NTP](https://vocal.com/resources/development/setting-the-time-on-an-embedded-linux-device-using-ntp/) - An embedded device without this hardware must synchronize its time with an external server every time it powers on or it will not know the correct time. - [Building Native Android Libraries](https://vocal.com/resources/development/building-native-android-libraries/) - Most developers writing Android applications will use a high-level object-oriented language such as Java. - [Using SCP for File Transfer with Embedded Linux Systems](https://vocal.com/resources/development/using-scp-for-file-transfer-with-embedded-linux-systems/) - Using SCP for file transfer is similar to using the standard copy (cp) command. One difference is that scp supports a syntax for specifying remote paths. - [Adding a Custom Module to the Linux Kernel](https://vocal.com/resources/development/adding-a-custom-module-to-the-linux-kernel/) - A Linux kernel module contains code that can be added or removed from the kernel at runtime using command line utilities (insmod, rmmod). - [Implementing Callback Functions in C# Wrappers for Native Code](https://vocal.com/resources/development/implementing-callback-functions-in-c-sharp-wrappers-for-native-code/) - Many applications written in high-level programming languages such as C# must interact with programs written in lower-level languages, such as C. - [Overview of Environment Variables in Linux](https://vocal.com/resources/development/overview-of-environment-variables-in-linux/) - The environment variables available to the command prompt can be used in commands and shell scripts. - [Using a Custom Linux Kernel in Buildroot](https://vocal.com/resources/development/using-a-custom-linux-kernel-in-buildroot/) - Using a custom Linux kernel in Buildroot can be done by using the Buildroot package override feature. - [Using Asynchronous Processing in JavaScript](https://vocal.com/resources/development/using-asynchronous-processing-in-javascript/) - Internet applications, such as those that use WebRTC, are often implemented in JavaScript when browser support is required. - [Using Multi-Planar Image Formats](https://vocal.com/resources/development/using-multi-planar-image-formats/) - For the RGB example, a multi-planar image format would have all the red, green, and blue values stored in different sections of memmory - [Using pthread Conditions for Thread Synchronization](https://vocal.com/resources/development/using-pthread-conditions-for-thread-synchronization/) - With pthread conditions, the Linux kernel handles waking the processing thread when another thread signals the condition. - [Using the I2C Bus in Linux Kernel Space](https://vocal.com/resources/development/using-the-i2c-bus-in-linux-kernel-space/) - If the microcontroller is running Linux, it can use the Linux I2C methods for reading and writing register values on the peripheral devices. - [Using the Linux I2C-Tools Software](https://vocal.com/resources/development/using-the-linux-i2c-tools-software/) - When developing software for embedded devices that use I2C, it is often useful to try out different register values on peripheral devices to find out what combinations work. - [Decision Making in Linux Shell Scripts](https://vocal.com/resources/development/decision-making-in-linux-shell-scripts/) - Linux shell scripts are used for automation, and automation usually requires decision making. There are a few ways to make decisions in shell scripts. - [Functions in Linux Shell Scripts](https://vocal.com/resources/development/functions-in-linux-shell-scripts/) - Instead of typing out the same code in each context, the code can go in a function and the function can be called by its name. - [Overview of Makefiles](https://vocal.com/resources/development/overview-of-makefiles/) - Makefiles are scripts that can be run by the ‘make’ command. A makefile is composed of a set of rules. - [Parsing Text Files Line by Line](https://vocal.com/resources/development/parsing-text-files-line-by-line/) - Scripts can easily parse for lines that match a pattern, and perform some operation when a match is found. - [Scripting with U-Boot Environment Variables](https://vocal.com/resources/development/scripting-with-u-boot-environment-variables/) - The main purpose of the U-Boot boot loader is to locate the image for the operating system (usually Linux), load it into RAM and run it. - [Using GStreamer Pad Probes](https://vocal.com/resources/development/using-gstreamer-pad-probes/) - Pad probes are callbacks that GStreamer pads call at various stages of sending and receiving buffers and events. - [Using LibAV for Video Encoding and Decoding](https://vocal.com/resources/development/using-libav-for-video-encoding-and-decoding/) - LibAV is an open source library that implements many video encoders and decoders. - [Using the OpenGL Shading Language for Pixel Format Conversion](https://vocal.com/resources/development/using-the-opengl-shading-language-for-pixel-format-conversion/) - OpenGL has functions for creating shader programs, setting their source code and compiling them. - [Using Thread Local Storage](https://vocal.com/resources/development/using-thread-local-storage/) - When developing multi-threaded applications using low-level languages such as C, the concept of thread local storage comes up occasionally. - [How do I Use OpenSLES for Audio in Native Android Libraries?](https://vocal.com/resources/development/how-do-i-use-opensles-for-audio-in-native-android-libraries/) - The Java interface includes all the functionality needed to play and record audio in Android applications. - [How do I Use DependencyService in Xamarin?](https://vocal.com/resources/development/how-do-i-use-dependencyservice-in-xamarin/) - Xamarin is widely used to develop applications for mobile devices, it uses C# as its programming language - [How do I Build Native Libraries for iOS Applications?](https://vocal.com/resources/development/how-do-i-build-native-libraries-for-ios-applications/) - Building applications for iOS is always done using XCode, which comes with a number of tools that are used at various stages of the development process. - [Requirements for Acoustic Echo Cancellation and Noise Reduction](https://vocal.com/echo-cancellation/requirements/) - VOCAL's Acoustic Echo Cancellation and noise reduction software provide superior audio quality in noisy environments. - [Optimizing Deep Neural Networks](https://vocal.com/noise-reduction/optimizing-deep-neural-networks/) - The effectiveness of Deep Neural Networks at improving the speech intelligibility of noisy signals has made them an attractive solution. - [Nullforming for Physical Layer Security](https://vocal.com/beamforming-2/nullforming-for-physical-layer-security/) - Beamforming and Nullforming provide a great starting point for physical layer security for multi-antenna wireless communication devices. - [SoIP - Serial over IP Gateway Reference Design](https://vocal.com/system-designs/serial-over-ip-reference-design/) - VOCAL's SoIP, Serial Over IP Gateway Reference Design Kits enable licensees to develop a variety of standards-based next generation product configurations. - [Secure Internet Message Access Protocol - IMAP Over SSL /TLS](https://vocal.com/secure-communication/secure-imap-over-ssltls/) - Internet Message Access Protocol, IMAP Protocol, or IMAP over SSL v3 / TLSv1 uses the STARTTLS extension mechanism to provide secure message transport. - [Voice Activity Detection (VAD)](https://vocal.com/noise-reduction/a-basic-voice-activity-detection-vad/) - Voice Activity Detection performance can dramatically influence noise reduction and speech distortion severity. - [Speech Enhancement Software - Speech Enhancer](https://vocal.com/voice-quality-enhancement/speech-audio-enhancement/) - Speech enhancer or speech enhancement software optimized for DSPs provides superior audio and speech quality in challenging communications environments. - [Minimum Variance Distortionless Response (MVDR) Beamformer](https://vocal.com/beamforming-2/minimum-variance-distortionless-response-mvdr-beamformer/) - The MVDR Beamformer is a data adaptive beamforming solution whose goal is to minimize the variance of the recorded signal. - [EAPoL Protocol - Extensible Authentication Protocol over LAN](https://vocal.com/secure-communication/eapol-extensible-authentication-protocol-over-lan/) - EAPoL Protocol or Extensible Authentication Protocol over LAN is a generic network sign-on method for IEEE 802.1X Port Based Network Access Control. - [EAPoW - Extensible Authentication Protocol over Wireless](https://vocal.com/secure-communication/eapow-extensible-authentication-protocol-over-wireless/) - EAPoW - Extensible Authentication Protocol over Wireless (IEEE 802.11) delivers session WEP keys to wireless network users - [Bluetooth Audio and Echo Cancellation: Compression Considerations](https://vocal.com/echo-cancellation/bluetooth-audio-and-echo-cancellation-compression-considerations/) - The compression and transmission errors introduced by Bluetooth communications creates challenges for acoustic echo cancellation software. - [Automatic Gain and Saturation Control for an Acoustic Echo Canceller](https://vocal.com/echo-cancellation/automatic-gain-and-saturation-control-for-an-acoustic-echo-canceller/) - Automatic gain and saturation control is required to meet optimal operational performance of an acoustic echo canceller. - [Video Conferencing Technology](https://vocal.com/video/video-conferencing-technology/) - Our video conferencing technology designs enable simultaneous communication using video, audio, still images and text. Call to discuss your video requirements! - [CCM](https://vocal.com/cryptography/ccm/) - VOCAL's CCM (Counter with Cipher Block Chaining-Message Authentication Code) algorithm provides assurance of confidentiality and authenticity of data. - [Mobile Voice over IP Technology using H.323](https://vocal.com/voip/mobile-voice-over-ip-technology-using-h-323/) - Mobile VoIP using H.323 enables mobile phones and devices to initiate and receive VoIP calls. Call us to learn more! - [Dynamic Time Warping Algorithm](https://vocal.com/echo-cancellation/dynamic-time-warping/) - The Dynamic Time Warping algorithm aligns two audio streams by warping the time axis iteratively until an optimal match is found. Contact us today! - [SHA-1 and SHA-2 (SHA-224, SHA-256, SHA-384, SHA-512) Hashing Algorithm](https://vocal.com/cryptography/sha-algorithm/) - Our wide range of hardware and software cryptographic solutions include SHA-1 and SHA-2 (SHA-256) Hash encryption algorithms used to generate a message digest. - [Serial over IP Integrated Communicator](https://vocal.com/system-designs/vocal-serial-over-ip-integrated-communicator/) - VOCAL's VIC-X product line implements special configurations of this hardware with customized application-specific operating software. - [Speech Composition for Recognition](https://vocal.com/speech-recognition/speech-composition/) - VOCAL's speech recognition processing classifies the specific sound characteristics of phonemes to determine what words are spoken - [Managing Different Aspect Ratios in Video Displays](https://vocal.com/video/managing-different-aspect-ratios-in-video-displays/) - When rendering live video streams to a fixed viewport, sometimes the video stream will have a different aspect ratio from the viewport. - [Wideband Acoustic Beamforming Frequency Response Evaluation](https://vocal.com/beamforming-2/wideband-acoustic-beamforming-frequency-response-evaluation/) - After the high-level functionality of a microphone array has been verified, the next step is to verify the performance of the beamformer. - [How can beamforming create power?](https://vocal.com/beamforming-2/how-can-beamforming-create-power/) - How can beamforming create power? In this short article we describe a very interesting but mind-bugging phenomenon in beamforming. - [Choice of Loss Function for Neural Networks](https://vocal.com/noise-reduction/choice-of-loss-function-for-neural-networks/) - Neural networks are often attempting to model non-linear systems. It is still desirable for cost (or loss) functions to use linear or logistic regression. - [Baseband Frequency Locking for Distributed Transmit Beamforming](https://vocal.com/beamforming-2/baseband-frequency-locking-beamforming/) - Baseband Frequency Locking for Distributed Transmit Beamforming. Frequency locking is essential for untethered sensor nodes forming a maximum beam at a receiver - [TSVCIS Improves Speech Quality](https://vocal.com/speech-coders/tsvcis-melpe/tsvcis-improves-speech-quality/) - Tactical Secure Voice Cryptographic Interoperability Specification, TSVCIS speech quality utilizes a variable data rate speech coder, & forward error correction - [Pre-filter Microphone Signals for Acoustic Beamforming](https://vocal.com/beamforming-2/pre-filter-microphone-signals-for-acoustic-beamforming/) - Pre-filter Microphone Signals for Acoustic Beamforming. By prefiltering the microphone signals the overall performance of the beamformer will be improved. - [Radar-communication spectrum sharing](https://vocal.com/5g/radar-communication-spectrum-sharing/) - With the ongoing congestion of wireless spectrum in the forthcoming 5G era, spectrum sharing has received significant attention in the past years. - [Bluetooth Audio and Echo Cancellation: Delay Considerations](https://vocal.com/echo-cancellation/bluetooth-audio-and-echo-cancellation-delay-considerations/) - For full duplex devices using Bluetooth, an AEC solution with fast reconvergence properties is needed. - [Echo Control on Codec Parameters](https://vocal.com/echo-cancellation/echo-control/) - This direct modification of the codec parameters provides low complexity solution to voice quality enhancement in cellular networks. - [Double-Talk Detection in Echo Cancellation](https://vocal.com/echo-cancellation/double-talk-detector-in-echo-cancellation/) - DTD enables the echo canceller to cancel echo reliably and transmit clear speech upstream. Call us to discuss your DTD and echo canceller application - [Microphone Noise Reduction](https://vocal.com/noise-reduction/microphone-noise-reduction/) - Microphone noise reduction techniques capture the signal of interest while removing background noise. Contact us to learn more! - [Activation Functions of Neural Networks](https://vocal.com/speech-recognition/activation-functions-of-neural-networks/) - The ability to model unknown systems come from activation functions, which are required for mapping non-linearly problems into a linear space. - [RISC–V Software Modules](https://vocal.com/software-modules/risc-v-software-modules/) - RISC–V is a free and open instruction set architecture (ISA) based on the load and store reduced instruction set computer. - [Vanishing Gradient of Deep Neural Networks](https://vocal.com/speech-recognition/vanishing-gradient-of-deep-neural-networks/) - TDeep Neural Networks (DNN) can be applied to speech enhancement, speech coding and speech recognition tasks. The vanishing gradient is a common problem of DNN. - [Testing and Verifying Microphone Arrays](https://vocal.com/beamforming-2/test-and-verify-microphone-arrays-2/) - There are multiple perturbations that can occur that will prevent a beamforming algorithm from reaching its theoretical performance. - [Practice of RT60 Estimation in Bands](https://vocal.com/dereverberation/practice-of-rt60-estimation-in-bands/) - RT60 and other acoustic parameter estimates are important for acoustic/audio practices involving experiments in rooms and closed spaces. Call us today! - [Volterra AEC](https://vocal.com/echo-cancellation/volterra-aec/) - Echo path components are nonlinear and can be represented in a non-linear system as a Volterra series. Contact us to learn more! - [JPSEC Authentication Template](https://vocal.com/secure-communication/jpsec-authentication-template/) - The authentication template conveys to the verifier how to verify the authenticity of the received codestream. There are 3 general classes of authentication. - [Satellite Communications Solutions](https://vocal.com/specialties/satellite-communications-solutions/) - In addition to geostationary satellites providing legacy telecom services, there are many new providers; some with just a few satellites. - [Distributed Transmit Beamforming](https://vocal.com/beamforming-2/distributed-transmit-beamforming/) - Distributed transmit beamforming is a communication scheme where a number of untethered transmitter nodes organize themselves into a virtual antenna array. - [EAP Types - Extensible Authentication Protocol Types information](https://vocal.com/secure-communication/eap-types/) - Vocal Technologies has provided a list of Extensible Authentication Protocol (EAP) Types and References for you to use. - [JPSEC Tools](https://vocal.com/secure-communication/jpsec-tools/) - There are two classes of JPSEC tools normative and non-normative. The normative are defined with the protection method templates specified in the tool syntax. - [JPSEC Registration Authority (RA)](https://vocal.com/secure-communication/jpsec-registration-authority-ra/) - JPSEC Registration Authority (RA) maintains a reference list.to identify JPSEC tools by a unique marker in the codestream - [JPSEC Key Information Template](https://vocal.com/secure-communication/jpsec-key-information-template/) - JPSEC key information template passes the key information to the other templates that provide security services to JPEG 2000 codestreams - [JPSEC Hash Template](https://vocal.com/secure-communication/jpsec-hash-template/) - The Hash Template uses two 8-bit values , hash function identifier and size of hash value, to convey the parameters used to compute the hash on the JPSEC data. - [JPSEC Decryption Template](https://vocal.com/secure-communication/jpsec-authentication-template-2/) - The decryption template conveys to the decryptor how to decrypt received codestream. There are 3 types of ciphers specified in the JPSEC standard: - [JPSEC: Secure JPEG2000](https://vocal.com/secure-communication/jpsec-secure-jpeg2000/) - The newest standard published by the Joint Photographic Experts Group (JPEG) committee is JPEG2000 and has many advantages over the currently used JPEG standard - [Linux Driver Model for SoC Audio](https://vocal.com/speech-coders/linux-driver-model-for-soc-audio/) - The Linux kernel has built-in support for SoC audio chips, and understanding its architecture can help in developing drivers for custom hardware. - [Objective Testing of Speech Enhancement Algorithms](https://vocal.com/voice-quality-enhancement/objective-testing-of-speech-enhancement-algorithms/) - Objective testing is preferred over subjective testing during the intermediate stages of development of speech enhancement algorithms - [Hilbert Transform in Signal Processing](https://vocal.com/voice-quality-enhancement/hilbert-transform/) - The Hilbert transform plays a significant role in signal processing and many other areas of science and engineering such as seismology and medical applications. - [Supervised Learning for DNN Speech Enhancement](https://vocal.com/noise-reduction/supervised-learning-for-dnn-speech-enhancement/) - During supervised learning for Deep Neural Network (DNN Speech Enhancement), the desired speech signal is available as reference to train the network. - [Room Impulse Response](https://vocal.com/dereverberation/room-impulse-response/) - VOCAL's speech enhancement software uses Cepstrum Analysis and LP Residual algorithms to estimate and remove the Room Impulse Response from the speech signal - [Viterbi Algorithm in Speech Enhancement and HMM](https://vocal.com/echo-cancellation/viterbi-algorithm-in-speech-enhancement-and-hmm/) - Viterbi algorithm is used to decode convolutional codes (CDMA, GSM, etc) and in speech recognition, speech synthesis and speech enhancement. Contact us today! - [MISRA C Coding Standard Impact on Signal Processing Algorithms](https://vocal.com/speech-processing-and-audio/misra-c-coding-standard-impact-on-signal-processing-algorithms/) - The MISRA C coding standard was developed to preserve the features of C, while eliminating some of the pitfalls that could result in safety and security issues. - [Introduction to MISRA C](https://vocal.com/resources/introduction-to-misra-c/) - The goal of the MISRA C coding standard is to preserve the features of C, while eliminating some of the pitfalls that could result in safety and security issues - [Subband Acoustic Echo Cancellation with Variable Echo Tail Lengths](https://vocal.com/echo-cancellation/subband-acoustic-echo-cancellation-with-variable-echo-tail-lengths/) - Subband acoustic echo cancellation with variable echo tail lengths are the ideal framework to take advantage of the sound absorption characteristics. - [Categories of Digital Audio Watermarking Embedding and Detection](https://vocal.com/audio/digital-audio-watermarking/categories-of-digital-audio-watermarking-embedding-and-detection/) - Audio Watermarking methods can be classified as time domain or transform domain based, informed or non-informed, blind or non-blind. - [Acoustic Echo Cancellation with Expanded Dynamic Range](https://vocal.com/echo-cancellation/acoustic-echo-canceller/acoustic-echo-cancellation-with-expanded-dynamic-range/) - Adding bits and dynamic range improves the audio quality by lowering the noise floor and increasing the SNR of the audio signal. - [Neural Network Monaural Feature Selection for Speech Enhancement](https://vocal.com/noise-reduction/neural-network-monaural-feature-selection-for-speech-enhancement/) - Input feature selection plays an important role in the design of Speech Enhancement software utilizing neural networks. - [Multi-channel AEC Performance Tradeoffs](https://vocal.com/echo-cancellation/multi-channel-aec-performance-tradeoffs/) - There is a performance tradeoff between multi-channel acoustic echo cancellation (AEC) software configurations. - [ICE: Interactive Connectivity Establishment](https://vocal.com/networking/ice-interactive-connectivity-establishment/) - Interactive Connectivity Establishment (ICE) is used for NAT transversal VoIP and WebRTC media sessions. Call to discuss your application requirements - [Adaptive Filter Algorithm Stability](https://vocal.com/echo-cancellation/adaptive-filter-algorithm-stability/) - Adaptive Filters can become unstable during adaptation and impact echo canceller performance. Call us to learn more! - [Maintaining the Harmonic Structures for Speech Enhancement](https://vocal.com/voice-quality-enhancement/harmonic-structures/) - VOCAL's Speech Enhancement software reconstructs harmonic structures for improved speech quality in adverse acoustic environments - [Removing musical noise from denoised speech](https://vocal.com/voice-quality-enhancement/removing-musical-noise-from-denoised-speech/) - Denoising speech signals to enhance the quality of communication channels is a non trivial issue. Most approaches reducing noise introduce their own artifacts. - [Angle of Arrival Estimation For Broadband Acoustic Signals](https://vocal.com/beamforming-2/root-music-sub-band-aoa-estimation/) - Angle of arrival estimation based of generalized correlation coefficients are generally limited in accuracy by the maximum allowable delay samples. - [Blind source separation using DUET-like algorithm](https://vocal.com/beamforming-2/blind-source-separation-using-duet-like-algorithm/) - If frequency representations do not overlap, then any number of sources can be separated using a minimum of two microphones with Blind source separation. - [Implementing MUSIC Algorithm](https://vocal.com/beamforming-2/implement-music-algorithm/) - For a general microphone array, each element has a response to a source that is a function of the source direction. - [Vocoder Transcoding Software](https://vocal.com/speech-coders/voice-codec-transcoding/) - VOCAL’s vocoder transcoding software, optimized for leading DSPs and microprocessors, converts voice streams from one voice codec to another - [VOCAL's VoIP Software Stack Includes Android Optimized ITU, GSM](https://vocal.com/press-releases/pr-voip-stack-vocoders-android/) - VOCAL’s VoIP Software Stack includes ITU, GSM and wideband Android speech coders for enhanced voice quality and improved mobile internet calling. - [Critically Sampled Uniform Sub-Band EC using LMS-type Algorithms](https://vocal.com/echo-cancellation/uniform-sub-band-echo-cancellation-using-lms/) - Critically sampled uniform sub-band Echo Cancellation with LMS improves algorithm convergence and reduces echo propagation - [Psychoacoustic Echo Cancellation](https://vocal.com/echo-cancellation/psychoacoustic-echo-cancellation/) - VOCAL's psycho-acoustic echo cancellation algorithms provide computational efficiency and improve subjective output - [Double-Talk Detection (DTD)](https://vocal.com/echo-cancellation/double-talk-detection/) - Double-talk detectors prevent a near-end talker disrupting filter adaptation during far-end speech. Call to discuss your speech application requirements. - [Non-Linear AEC](https://vocal.com/echo-cancellation/non-linear-aec/) - Our Acoustic Echo Canceller includes non-linear AEC to handle non-linearities in the acoustic echo path for improved AEC performance, Contact us today! - [Analog TV Modulation](https://vocal.com/video/analog-tv-modulation/) - Since 1986 VOCAL has been designing innovative video solutions using NTSC, PAL, SECAM and other standards. Call to learn more! - [Working with Video Encoders](https://vocal.com/video/working-with-video-encoders/) - Video Encoders translate from streams of raw video images to compressed bitstreams. In streaming applications, video encoders are found on the sending side. - [Multi-mic Signal Processing: Nullforming for Noise Cancellation](https://vocal.com/beamforming-2/multi-mic-audio-signal-processing/nullforming-for-noise-cancellation/) - VOCAL Technologies offers custom designed multi-mic signal processing solutions to provide superior voice quality. - [Psychoacoustic Phenomena: Precedence Effect](https://vocal.com/audio/psychoacoustic-phenomena-precedence-effect/) - The Psychoacoustic Phenomena: Precedence Effect Explains How the auditory system resolves localization using direct and reflected sound. - [Using Noise Modeling for Speech Enhancement](https://vocal.com/noise-reduction/noise-modeling/) - Noise modeling for speech enhancement to determine parameters such as fundamental frequency, its important that the spectrum of the noise be taken into account. - [Iterative Spectrum Subtraction Noise Reduction](https://vocal.com/noise-reduction/iterative-spectrum-subtraction-noise-reduction/) - This small article describes the practical use of Iterative Wiener filtering in signal enhancement. Iterative Spectrum Subtraction Noise Reduction - [Deep Neural Networks Residual Echo Suppression](https://vocal.com/echo-cancellation/deep-neural-networks-residual-echo-suppression/) - Nonlinear Processing (NLP) and Residual Echo Suppression is required in real world acoustic echo cancellation (AEC) software. - [Mixing Matrix Estimation-Blind Source Separation of Far Field Sources](https://vocal.com/beamforming-2/mixing-matrix-estimation-for-blind-source-separation-of-far-field-sources/) - Blind source separation of far field source is used to recover an unknown number of sources using observable mixture signals. - [ITU G.711.1 Embedded Wideband Codec](https://vocal.com/speech-coders/itu-g-711-1-embedded-wideband-codec/) - VOCAL offers the G.711.1 codec software as a standalone algorithm, as part of a modular software library suite, as well as with a VoIP stack. - [Estimating ERL from AF FIR Taps](https://vocal.com/echo-cancellation/estimating-erl-from-af-fir-taps/) - Echo cancellation solutions are often equipped with miscellaneous additional functions that are designed for the purpose of system/network characterization.. - [DSP Developer Resources](https://vocal.com/resources/dsp-developer-resources/) - This page contains some hard-to-find technical resources for DSP engineers that we have found extremely useful over the course of more than 25 years. - [Consensus Based Synchronization For Distributed Transmit Beamforming](https://vocal.com/beamforming-2/consensus-based-synchronization-for-distributed-transmit-beamforming/) - Carrier synchronization is critical to any implementation of distributed transmit beamforming. Consensus Based Synch For Distributed Transmit Beamforming - [Fast Beamforming With Four Microphones For ASR Engines](https://vocal.com/beamforming-2/fast-beamforming-with-four-microphones-for-asr-engines/) - The use of automated speech recognition engines for mobile applications is on the rise. In theory, increasing the number of microphones affords increase in SNR. - [Working with Video Decoders](https://vocal.com/video/working-with-video-decoders/) - In video streaming applications, the decoder will typically receive bitstream data from the network, process that data, and send the raw images to be displayed. - [H.264/AVC Syntax](https://vocal.com/video/h-264-avc-syntax/) - VOCAL Technologies design solutions for H.264/AVC, which consist of a hierarchy of layers. The first layer is the Network Abstraction Layer (NAL). - [Stochastic Resonance](https://vocal.com/stochastic-resonance/) - Stochastic Resonance is a phenomenon that can change the perception of a problem with noise generated in signal processing. Read more about how this works. - [Teletics MoNet MoIP Gateway Implements VOCAL's Enhanced Modem](https://vocal.com/press-releases/monet-moip-gateway-uses-modem-over-ip/) - VOCAL’s Modem over IP solution is based on their Remote Access Server over IP (RASoIP)TM technology which combines networked remote access server functionality. - [Adaptive Beamformer with Poles and Zeros](https://vocal.com/beamforming-2/adaptive-beamformer-poles-zeros/) - Broadband beamforming processing can be interpreted as using an all-zero digital filter to generate a frequency-dependent magnitude and phase shift - [Acoustic Echo Cancellation (AEC) Barge-In](https://vocal.com/echo-cancellation/aec-barge-in/) - Modern Wakeup Word Detection (WWD) for Automatic Speech Recognition algorithms are fairly reliable when the SNR of the signal is just a few dB greater than 0. - [Efficient Implementation of LPC Analysis Filters](https://vocal.com/speech-coders/efficient-implementation-of-lpc-analysis-filters/) - In vocoders, Linear Prediction Coding (LPC) is used to whiten a speech signal so as to encode much of its shape. This allows the residual signal to be uniform. - [MPEG-4](https://vocal.com/video-codecs/mpeg-4/) - MPEG-4 is an advanced video coder used for motion picture video compression. Check back later for more information on the topic of MPEG-4. - [MJPEG](https://vocal.com/video-codecs/mjpeg/) - MJPEG is an advanced video coder used for motion picture video compression. Check back later for more information on the topic of MJPEG. - [The Cause of Echoes in Coding](https://vocal.com/voice-quality-enhancement/echoes-in-coding/) - Read about the cause of the pre-echoes is the quantization noise in the frequency domain when translated into the time domain for decoding. - [Error Correction Using Compressed Sensing Techniques](https://vocal.com/compressed-sensing/error-correction/) - Error Correction Using Compressed Sensing Techniques. Compressed sensing techniques can be used as a forward error correction scheme in signal processing. - [MPEG-2](https://vocal.com/video-codecs/mpeg-2/) - MPEG-2 is an advanced video coder used for motion picture video compression. Check back here for more information on the topic of MPEG-2 Codec. - [Weak Signal Detection Using PSO and SR](https://vocal.com/stochastic-resonance/weak-signal-detection/) - Stochastic Resonance (SR) can be used to help detect weak signals because of its ability to enhance periodic and aperiodic signals. - [Adaptive Antenna Arrays using Particle Swarm Optimization](https://vocal.com/particle-swarm-optimization/adaptive-antenna-arrays/) - Particle Swarm Optimization (PSO) is an algorithm first introduced in 1995 that was an outgrowth of a study of the flocking of birds. - [Current Proposed Modifications to T.38](https://vocal.com/voip/t-38-mods/) - To better distinguish the types of T.38 gateways, two definitions have been introduced. Those two definitions are "T.38/V.34G3" and "T.38/G3". - [Multicast and Unicast Streaming Media](https://vocal.com/networking/multicast-and-unicast-streaming-media/) - In a multicast transmission, an access point or (AP) has several nodes that it is transmitting to that require the streaming media. - [802.11 Authentication and Association](https://vocal.com/networking/802-11-authentication-and-association/) - 802.11 authentication and association provides a method for supplying different levels of access to different nodes in a wireless local area network (WLAN). - [Stochastic Resonance of Analog and Digital Signals](https://vocal.com/stochastic-resonance/analog-digital-signals/) - Stochastic Resonance (SR) of Analog and Digital Signals is a phenomenon where noise can be used to enhance a signal and was first discovered for analog signals. - [Euclidean Particle Swarm Optimization (EPSO)](https://vocal.com/particle-swarm-optimization/euclidean/) - Particle Swarm Optimization (PSO) is an optimization algorithm based on the idea that a collective is more than the sum of its parts. - [Speakerphone](https://vocal.com/telephony-software/speakerphone/) - A full-duplex speakerphone or intercom device digitizes the signal coming out of its speaker. It then edits this info out of the signal it’s transmitting. - [Time Delay of Arrival (TDOA) using Particle Swarm Optimization (PSO)](https://vocal.com/particle-swarm-optimization/tdoa/) - Time Delay of Arrival (TDOA) is a method used for determining the location of a signal source using the received signal at multiple locations. - [JPEG](https://vocal.com/video-codecs/jpeg/) - JPEG is an advanced video coder used for still image video compression. Please check back at a later date for more information on this topic. - [JPEG 2000](https://vocal.com/video-codecs/jpeg-2000/) - JPEG2000 is a wavelet transform based image compression specification with superior performance and remarkable flexibility. - [Compressed Sensing](https://vocal.com/compressed-sensing/) - Compressed sensing (CS) is a theory which states that, assuming some conditions are met, a vector can be compressed and sampled simultaneously (hence the name). - [HTTPS: HTTP over SSL/TLS](https://vocal.com/secure-communication/http-over-ssltls/) - Hypertext Transfer Protocol (HTTP) was the first application layer protocol to be secured with Secure Socket Layer (SSL). - [ITU H.263](https://vocal.com/video-codecs/itu-h-263/) - H.263 is an advanced video coder used for video conference video compression. Check back at a later date for more information on this topic. - [Secure Application Configuration Access Protocol - ACAP over SSL/TLS](https://vocal.com/secure-communication/secure-acap-over-ssltls/) - Application Configuration Access Protocol (ACAP) over SSLv3/TLSv1 uses the STARTTLS extension mechanism to provide secure message transport. - [Echo Cancellation Audio Examples](https://vocal.com/audio-examples/echo-cancellation-audio-examples/) - VOCAL's audio examples for ITU G.165 and G.168 Echo Canceller software. ITU Echo Cancellation and Other Echo Cancellation Audio Examples. - [Wideband Acoustic Echo Cancellation](https://vocal.com/echo-cancellation/wideband/) - VOCAL's acoustic echo cancellation (AEC) software optimized for leading DSPs enhances voice quality in wideband audio teleconferencing. - [How to Choose a Speech Coder?](https://vocal.com/speech-coders/how-to-choose-a-speech-coder/) - VOCAL Technologies, Ltd. has a large offering of optimized ITU, GSM, wideband and industry standard voice codecs. Please contact us to learn more. - [Comb Filtering in Acoustics](https://vocal.com/dereverberation/comb-filtering/) - What is Comb Filtering? Comb filtering happens when two or more identical audio signals are mixed together with a slight delay between them. - [What is a WPA? WiFi Protected Access](https://vocal.com/secure-communication/wi-fi-protected-access-wpa/) - What is a WPA? Wi-Fi Protected Access (WPA) provides improved encryption and authentication capabilities to the IEEE 802.11 standard. - [What Is Video Compression Technology](https://vocal.com/video/video-compression-technology/) - What is video compression? What does compressing a video do? Video compression allows video to be stored in a smaller file or sent over a network more quickly. - [Optimal Sampling Rate for Audio Communications](https://vocal.com/audio/optimal-sampling-rate-for-audio-communications/) - One needs to determine what is the optimal sampling rate during the product design review of an audio communications product. - [RGB and YUV Color Space Conversion](https://vocal.com/video/rgb-and-yuv-color-space-conversion/) - YUV to RGB conversion translates between color spaces for displays and image/video processing. Contact us to discuss your video requirements. - [RC4 Encryption - RC4 Algorithm](https://vocal.com/cryptography/rc4-encryption-algoritm/) - What is RC4? RC4 Algorithm is a shared key stream cipher algorithm requiring a secure exchange of a shared key. RC4 Encryption is no longer considered secure. - [Classic STUN Protocol: Simple Traversal of UDP Through NAT](https://vocal.com/networking/classic-stun-simple-traversal-of-udp-through-nat/) - STUN protocol, or Simple Transversal of UDP Through NAT works by discovering the presence of a NAT, the type of NAT, and IP address assigned by the NAT. - [CCMP - Cipher Block Chaining](https://vocal.com/secure-communication/ccmp/) - VOCAL's Cipher Block Chaining CCMP encryption protocol is based on AES encryption algorithm using the Counter Mode with CBC-MAC (CCM) mode of operation. - [Near Field Acoustic Beamforming](https://vocal.com/beamforming-2/near-field-acoustic-beamforming-software/) - Near field acoustic beamforming has improved source localization for superior voice quality in audio conferencing. Call to discuss your voice application - [Software Components of Embedded Linux Systems](https://vocal.com/software-modules/embedded-software-modules/software-components-of-embedded-linux-systems/) - Most embedded Linux systems can be divided into three main software components: The boot loader, the Linux kernel and the file system. - [Overview of Video Capture in Linux](https://vocal.com/video/overview-of-video-capture-in-linux/) - The Linux kernel has a built-in API for video capture devices called Video for Linux (V4L2), allowing the implementation of video capture in linux. - [Scalable Distributed Transmit Nullforming](https://vocal.com/beamforming-2/scalable-distributed-transmit-nullforming/) - A dual of wireless distributed beamforming is nullforming, a spatial filtering technique used to limit the energy of a beam from a given direction. - [Fast And Efficient GCC Algorithm For Speech Angle Of Arrival Detection](https://vocal.com/beamforming-2/gcc-for-speech-aoa-detection/) - Due to computation and memory constraints of embedded DSPs, a fast and efficient GCC algorithm is required to achieve any meaningful gains for beamforming. - [Acoustic source localization using circular array microphones](https://vocal.com/beamforming-2/acoustic-source-localization-using-circular-array-microphones/) - We show an approach to localizing an acoustic source using a circular microphone topology. Acoustic source localization using circular microphone array. - [High resolution far field direction of arrival using three microphones](https://vocal.com/beamforming-2/high-resolution-far-field-direction-of-arrival-using-three-microphones/) - Increase the signal from desired direction versus signal from undesired direction. High resolution far field direction of arrival using three microphones - [First order adaptive differential microphone array beamforming](https://vocal.com/beamforming-2/first-order-adaptive-differential-microphone-array-beamforming/) - Differential beamforming using two microphones, and hence first order, has two different implementations.. Call to discuss your beamforming requirements. - [Fundamental Limits On Angle Of Arrival Estimation Error](https://vocal.com/beamforming-2/aoa-fundamental-limits/) - The larger the separation, the more flawed the assumption (Estimation Error) of the acoustic source signal impinging all microphones at a common angle is. - [Acoustic echo cancellation with the NLMS algorithm](https://vocal.com/beamforming-2/aec-with-the-nlms-algorithm/) - The first go-to algorithm for acoustic echo cancellation (AEC) is a the gradient descent least mean squared (LMS) algorithm. - [Statistical Optimal Beamformers-Reference Signal Beamformer](https://vocal.com/beamforming-2/statistical-optimal-beamformers-reference-signal-beamformer/) - The reference signal beamformer (RSB), is a popular because the direction of arrival of the desired signal needs not be known. - [Statistical Optimal Beamformers-Multiple Sidelobe Canceller](https://vocal.com/beamforming-2/statistical_optimal_beamformers_multiple_sidelobe_canceller/) - In statistical optimal beamformers, the filter weights used are dependent on the statistics of the received data. - [Statistical optimal beamformers with steering vector mismatch](https://vocal.com/beamforming-2/statistical-optimal-beamformers-with-steering-vector-mismatch/) - Statistical optimal beamformers are used for super-directive beamforming, where maximum energy of the steering vector is concentrated at fixed points. - [Double-talk detection based on orthogonality principle](https://vocal.com/beamforming-2/double-talk-detection-based-on-orthogonality-principle/) - The use of energy comparison to detect double-talk can detect both the presence of a near-end speaker and a non-convergent echo. - [Statistical Optimal Beamformers](https://vocal.com/beamforming-2/statistical-optimal-beamformers-linearly-constrained-minimum-variance-beamformer/) - In statistical optimal beamforming, the filter weights used are dependent on the statistics of the received data. - [Energy based algorithm for cross-talk detection](https://vocal.com/beamforming-2/energy-based-algorithm-for-cross-talk-detection/) - Cross-talk occurs in full duplex communication channels and is defined as the period when there is speech from both ends of the channel. - [Two microphone beamforming for hearing aids](https://vocal.com/beamforming-2/two-microphone-beamforming-for-hearing-aids/) - Microphone array beamforming is increasingly being used for hearing aids to reduce some inherent problems of single microphone output being amplified for users. - [Statistical optimal beamformers: generalized sidelobe canceler](https://vocal.com/beamforming-2/statistical-optimal-beamformers-generalized-sidelobe-canceler/) - The generalized sidelobe canceler (GSC) is an alternative formulation of the linearly constrained maximum beamformer (LCMV). - [Variable descent step size for AEC](https://vocal.com/beamforming-2/variable-descent-step-size-for-aec/) - A design challenge in AEC algorithms is the dual between fast convergence and cancellation accuracy in terms of ERLE. - [Out of band energy level based algorithm for cross-talk detection](https://vocal.com/beamforming-2/out-of-band-energy-level-based-algorithm-for-cross-talk-detection/) - The drawback in the use of Geigel algorithm for detection of cross-talk is that, when the far end speech is at least one magnitude of order higher in SPL levels - [Using OpenGL to Display Streaming Video](https://vocal.com/video/using-opengl-to-display-streaming-video/) - Streaming video displays usually require image scaling which is inherently handled by the OpenGL language. - [Using GStreamer with SIP Call Control](https://vocal.com/resources/research/video-research/gstreamer-debugging-tools/using-gstreamer-with-sip-call-control/) - Both SIP and GStreamer can be used together in a V2oIP application. SIP will establish the parameters for a call, and will configure a GStreamer pipeline. - [Timestamp Semantics in RTP Video Streaming](https://vocal.com/video/timestamp-semantics-in-rtp-video-streaming/) - The main purpose of an RTP timestamp in video streams is to assist in smooth playback of the decoded video frames on the receiving end. - [Testing ALSA Drivers with aplay and arecord](https://vocal.com/speech-coders/testing-alsa-drivers-with-aplay-and-arecord/) - Both aplay and arecord have numerous command line options to control which ALSA device is used and how that device is configured. - [Stride in Raw Video Images](https://vocal.com/video/stride-in-raw-video-images/) - The stride is usually the number of bytes from one row of the video image to the next. This is different from the width which is the number of pixels in a row. - [Signaling Methods for Video Streaming](https://vocal.com/video/signaling-methods-for-video-streaming/) - One reason for video signaling is to control the quality and bitrate of the stream for managing the CPU and bandwidth resources required by the stream. - [Pixel Format Conversions in Video Conferencing](https://vocal.com/video/video-conferencing-technology/pixel-format-conversions-in-video-conferencing/) - Major components of a video conferencing system include the capture, encode, decode and display systems. - [PC Video Software Design](https://vocal.com/software-modules/video-software/pc-video-software-design/) - VOCAL's software routs the camera's video stream to destinations such as video encoders for streaming over the network, or video displays for local preview. - [Identifying Audio Devices in ALSA](https://vocal.com/speech-coders/identifying-audio-devices-in-alsa/) - ALSA is composed of a Linux driver framework and a user-space API that together provide access to audio hardware. - [Drawing Text Overlays on Live Video Displays](https://vocal.com/video/drawing-text-overlays-on-live-video-displays/) - A frequent issue that appears in live video applications is how to label the various video streams that are being shown to the user. - [Buffer Management in Video Streaming Applications](https://vocal.com/video/buffer-management-in-video-streaming-applications/) - Applications that capture or display video usually need some buffer management to process un-compressed video images. - [ALSA Codec Configuration](https://vocal.com/speech-coders/alsa-codec-configuration/) - The microchip that implements the audio system (codec) can be controlled through various protocols allowing codec configuration. - [The Motivation for Deep Neural Network Speech Enhancement](https://vocal.com/noise-reduction/deep-neural-network-speech-enhancement/) - The speech enhancement classification problem is an ideal application for Deep Neural Networks (DNN) - [Reverberation and Acoustic Beamforming](https://vocal.com/beamforming-2/reverberation-and-acoustic-beamforming/) - The goal of an optimal beamformer is to minimize the interference and noise sources, while preserving the desired signal in a specific direction. - [Efficient Microphone Array Design for Acoustic Beamforming](https://vocal.com/beamforming-2/efficient-microphone-array-design-for-acoustic-beamforming/) - The goal of sound capture devices of acoustic beamforming is to provide a directional SNR improvement, while consuming as little power as possible. - [Bandwidth Extension](https://vocal.com/voice-quality-enhancement/bandwidth-extension/) - Bandwidth Extension (BWE) is used to convert speech signals from NB to WB to fill the upper portion (or even both ends) of the WB. Call us today to learn more! - [Autoregressive model for speech processing in frequency domain](https://vocal.com/voice-quality-enhancement/autoregressive-model-for-speech-processing-in-frequency-domain/) - A well known model for speech processing is the linear prediction model, which is accomplished in time domain. - [Other Speech Coder Audio Examples](https://vocal.com/audio-examples/other-speech-coder-audio-examples/) - VOCAL's Speech Coder software includes iLBC, LPC-10, MELP, MELPe, Speex, SILK modules optimized for leading DSPs and processors - [Wideband Speech Coder Audio Examples](https://vocal.com/audio-examples/wideband-speech-coder-audio-examples/) - VOCAL's Wideband Speech coders include G.722, G.722.1, G.722.2, GSM-AMR/WB, and Speex optimized for leading DSPs - [GSM Speech Coder Audio Examples](https://vocal.com/audio-examples/gsm-speech-coder-audio-examples/) - VOCAL GSM Speech Coder audio examples for GSM-FR, GSM-HR, GSM-EFR, GSM-AMR, GSM-AMR-WB voice compression software - [ITU Speech Coder Audio Examples](https://vocal.com/audio-examples/itu-speech-coder-audio-examples/) - Audio examples of VOCAL's ITU Speech Coders for G.711, G.721, G.722, G.722.1, G.722.2, G.723, G.723.1, G.726, G.728, G.729, G.729A, G.729AB - [Noise Cancellation Audio Examples](https://vocal.com/audio-examples/noise-cancellation-audio-examples/) - VOCAL's Noise Cancellation software optimized for leading DSPs is highly effective in battlefield and other noisy environments - [Microphone Array Phase Calibration for Beamforming](https://vocal.com/beamforming-2/microphone-array-phase-calibration-for-beamforming/) - In order to minimize the phase mismatch a calibration procedure is required. Calibration methods can be performed at the factory or during an installation. - [Robust Maximum Directivity Factor Beamforming](https://vocal.com/beamforming-2/robust-maximum-df-beamforming/) - DF beamforming is a generalized case of the Superdirective beamformer where the desired look direction and the inter-element spacing is small. - [Microphone Array Magnitude Calibration for Beamforming](https://vocal.com/beamforming-2/microphone-array-magnitude-calibration-for-beamforming/) - The far-field sound propagation model is often used in the design of beamforming algorithms for a microphone array. - [Filter Banks](https://vocal.com/audio/filter-banks/) - A filter bank is a set of bandpass filters with uniform or nonuniformly separated subbands. It is utilized in both the encoding and decoding processes. - [Bessel and Hankel Functions](https://vocal.com/resources/bessel-and-hankel-functions/) - The Bessel and hankel function is a special function in mathematics that expresses inward or outward propagating waveforms. - [Binaural LCMV Beamforming](https://vocal.com/beamforming-2/binaural-lcmv-beamforming/) - In order to preserve the cues of the interfering sources, additional constraints are introduced into the system, making the Binaural LCMV beamformer. - [Cylindrical Modal Beamforming Using a Circular Microphone Array](https://vocal.com/beamforming-2/cylindrical-modal-beamforming-using-a-circular-microphone-array/) - When dealing with circular arrays, we take advantage of its azimuthal symmetry by utilizing the cylindrical harmonic decomposition for Modal Beamforming. - [Single Microphone Active Noise Cancellation](https://vocal.com/noise-reduction/single-microphone-active-noise-cancellation/) - A Single Microphone Active Noise Cancellation System will comprise of at least one microphone and one speaker to feedback the destructive signal for canceling. - [Stereo and Surround Sound Acoustic Feedback/Echo Cancellation](https://vocal.com/echo-cancellation/stereo-and-surround-sound-acoustic-feedback-echo-cancellation/) - Stereo or surround sound acoustic cancellation can be considered as a special case of multi-channel cancellation with one main difference. - [Multi-Channel Acoustic Feedback/Echo Cancellation](https://vocal.com/echo-cancellation/multi-channel-acoustic-feedback-echo-cancellation/) - VOCAL Technologies has developed solution libraries that help facilitate Multi-Channel Acoustic Feedback and Echo Cancellation problems. - [Lawful Interception Research Resources](https://vocal.com/resources/research/lawful-interception/) - Lawful Interception is the intercept of data on a network as authorized by a law enforcement agency. - [Echo Cancellation Research](https://vocal.com/resources/research/echo-cancellation-design/) - VOCAL continues to research applications of echo cancellation to voice communications, audio conferencing and speech recognition - [Lawful Interception Reference Designs](https://vocal.com/resources/reference-designs/lawful-interception/) - Our design solutions are used for lawful interception and decoding of voice and fax communications over PSTN and IP networks. Contact us today! - [Stereo and Surround Sound Acoustic Feedback / EC](https://vocal.com/echo-cancellation/stereo-and-surround-sound-acoustic-feedback-echo-cancellation-2/) - VOCAL Technologies has developed a solution library to address drawbacks to normal approaches to acoustic feedback and echo cancellation. - [VOCAL Provides the Voice for Sorenson Hybrid Chips](https://vocal.com/press-releases/vocal-provides-the-voice-for-sorenson-svx-hybrid-chips/) - VOCAL's software solution integrates voice compression, line, and acoustic echo cancellation on single DSP - [VOCAL Software Enables WLAN Implementation](https://vocal.com/press-releases/vocal-software-enables-wlan-hardware-implementation/) - VOCAL's software solutions support fast time to market for WLAN ICs using 802.11a, 802.11b, and 802.11g standards - [VOCAL Software Translates Video For 2.5G/3G Handsets](https://vocal.com/press-releases/vocal-software-translates-video-for-2-5g3g-wireless-handsets/) - VOCAL's vocoder and videocoder software solution enables Internet video, audio, and text messaging from 2.5G/3G wireless phones. - [VOCAL Inks Accord With Agilent Technologies](https://vocal.com/press-releases/vocal-technologies-inks-accord-with-agilent-technologies/) - Agilent Technologies adds VOCAL's Fax modem image processing software to SOC design for multi-function peripheral (MFP) device - [VoIP Research Resources](https://vocal.com/resources/research/voip-research-resources/) - VOCAL continues to research issues and uses of advanced technologies for voice, video, fax and data communications using VoIP protocols. Call us today! - [Echo Cancellation Reference Designs](https://vocal.com/resources/reference-designs/echo-cancellation-reference/) - VOCAL offers a range of Echo Cancellation Reference Designs for voice communications over radio, mobile and IP networks. - [Data Modem Reference Designs](https://vocal.com/resources/reference-designs/data/) - Data Modem Reference Designs for legacy modem applications and modem communications over PSTN, radio, mobile, IP and satellite networks. Call us to learn more! - [Communication Security Reference Designs](https://vocal.com/resources/reference-designs/communication-security/) - Our Reference Designs support secure voice, video, fax and data communications over radio, mobile and IP networks. Contact us today! - [Counter with Cipher Block Chaining-Message Authentication Code](https://vocal.com/hardware-reference-designs/ccm-ip-core/) - VOCAL's Hardware/Firmware implementation of the Counter with CCM optimized for leading DSPs supports AES for improved security - [Image Compression Using Compressed Sensing & PSO](https://vocal.com/particle-swarm-optimization/image-compression/) - VOCAL's Particle Swarm Optimization and Compressed Sensing software offers improved algorithm performance for image compression - [VOCAL Announces Single-Processor VoIP-Analog Telephone Adapter](https://vocal.com/press-releases/vocal-announces-single-processor-voip-analog-telephone-adapter-based-on-tms320c55x-dsp-from-texas-instruments/) - A single-processor design announced today by VOCAL Technologies, Ltd. (www.vocal.com) will enable the development of inexpensive equipment. - [VOCAL Helps Utility Companies Overcome Meter Reading Challenges](https://vocal.com/press-releases/utility_meter_modem_voip/) - VOCAL Technologies Helps Utility Companies Worldwide Overcome Meter Reading Challenges With New SAMS Solution - [New Internet PBX ATA (iPBX) & PBXtender Extends VoIP to Homes, Offices](https://vocal.com/press-releases/vocal-technologies-unveils-new-internet-pbx-ata-ipbx-and-pbxtender-to-extend-voip-service-in-homes-offices/) - Our Internet PBX ATA (iPBX) and PBXtender enables residential and professional users to extend VoIP service throughout their home or office - [Enhanced TR-069 VoIP Stack For Lawful Interception Assets](https://vocal.com/press-releases/enhanced-tr-069-voip-stack/) - VOCAL’s enhanced TR-069 Stack enables dynamic reconfiguration and provisioning of Fax Lawful Interception Assets over IP networks - [PSO in the RWA Process for All-Optical WDM Networks](https://vocal.com/particle-swarm-optimization/wdm-networks/) - Particle Swarm Optimization is used to determine the optimal Routing and Wavelength Assignment for an all optical Wavelength Division Multiplexing network. - [Multi-Channel Video Framework Unleashes Potential of DaVinci DM8168](https://vocal.com/press-releases/multi-channel-video-framework-dm8168/) - VOCAL’s Multi-Channel Video Framework (MCVF) for the TI DaVinci TMS320DM81XX family of media processors supports simultaneous SD and HD H.264 video channels - [VOCAL & Tilgin to Leverage TR-069 for Enhanced Customer Services](https://vocal.com/press-releases/tr-069-enhanced-services/) - VOCAL's TR-069 Client Software Stack demonstrates proven interoperability with Tilgin ACS and other standards based vendor products. - [AEC Plus Integrates Speech Enhancement, AGC and Echo Tail Search](https://vocal.com/press-releases/acoustic-echo-cancellation-plus/) - Acoustic Echo Cancellation Plus provides built-in speech enhancement, AGC, and echo tail search for superior voice quality and ease of product integration - [PSO in the Grassmannian Line Packing Problem for MIMO Beamforming](https://vocal.com/particle-swarm-optimization/grassmannian/) - Particle Swarm Optimization is used to solve the Grassmannian line packing problem for the offline design of MIMO codebooks. - [Narrow Passband Spectrum Filtering by Downsampling & Trivial Rotation](https://vocal.com/video/narrow-passband-spectrum-filtering-by-downsampling-and-trivial-rotation/) - Filtering to extract a narrow part of the input spectrum is a common problem. Call to discuss your video signal application requirements - [Distortion Minimizing Rate Control for Wireless Multimedia Networks](https://vocal.com/networking/distortion-minimizing-rate-control/) - Wireless multimedia sensor networks use distortion minimizing rate control (DMRC) to maintain fairness among different streams and consistent data rates - [VOCAL Teams with SOC Technology for Production of VoIP Speaker Phone](https://vocal.com/press-releases/vocal-technologies-ltd-teams-with-soc-technology-gmbh-co-kg-for-production-of-voip-speaker-phone/) - German manufacturer of ASIC and System-on-Chip Designs, has adopted VOCAL’s new VoIP Speaker Phone Reference design for production slated to begin this Autumn. - [New Adapters from VOCAL enhance VOIP service, accommodate more phones](https://vocal.com/press-releases/new-adapters-enhance-voip-services-more-phones/) - VOCAL's Analog Telephone Adapter (ATA) reference design supports enhanced VOIP performance and telephone functionality - [Errors in Localization using Non-individualized Head-Related Transfers](https://vocal.com/audio/errors-in-localization-using-non-individualized-head-related-transfer-functions/) - Head geometry makes head-related transfer functions highly idiosyncratic, It's imperative to represent these characteristics during a spatial audio rendering. - [Eigen Space Voice Activity Detector for Multiple Microphone Array](https://vocal.com/voice-quality-enhancement/eigen-space-voice-activity-detector-for-multiple-microphone-array-broadband-acoustics/) - Received signal energy based voice activity detectors, Voice Activity Detectors, are widely employed in broadband acoustic systems. - [Classification Model Assessment and Validation for Voice Detection](https://vocal.com/voice-quality-enhancement/classification-model-for-vad/) - Our extensive model validation software assures your Voice Activity Detection solution is optimal for your voice application requirements - [AEC for Commercial Off-the-Shelf (COTS) Hardware](https://vocal.com/echo-cancellation/cots-hardware/) - VOCAL's acoustic echo cancellation solution enhances voice quality for all major COTS operating systems and processors. - [VOCAL Provides Its AES-128 for DTCP Using Microprocessors](https://vocal.com/press-releases/vocal-provides-its-aes-128-for-dtcp-using-industry-standard-microprocessors/) - VOCAL announces the availability of its AES-128 as a processor extension for Digital Transmission Content Protocol (DTCP). - [Implementation of FIR with Steep Rolloff & High Level of Attenuation](https://vocal.com/video/fir-with-steep-rolloff-and-high-level-of-attenuation-stopband/) - FIR digital filters with symmetrical impulse response have exact linear phase response needed for video processing. Call to discuss your video application! - [VOCAL Extends the Longevity of Payment Processing with SAMS](https://vocal.com/press-releases/point_of_sale_modem_voip/) - VOCAL Technologies Extends the Longevity of Dial-In Point-of-Sale Payment Processing with New SAMS Solution - [Convergence Speed Optimization for NLMS Algorithm](https://vocal.com/echo-cancellation/convergence-speed-optimization-for-normalized-least-mean-square-nlms-algorithm/) - Normalized Least Mean Square (NLMS) can be used in a wide range of applications, including echo and feedback cancellation and impulse response estimation. - [VOCALs Comprehensive Fax Diag Troubleshoot Fax Transmission Issues](https://vocal.com/press-releases/comprehensive-fax-diagnostics/) - VOCAL’s modular fax software stack with comprehensive diagnostics extends Axacore facsimile products to quickly troubleshoot fax transmissions - [Generalized Solution to the Minimum Variance Distortionless Response](https://vocal.com/voice-quality-enhancement/gen-solution-min-variance-distortionless-response-broadband-audio/) - In minimum variance distortionless response, the filter coefficients used to remove noise and interfering signals are adjusted based on the statistics - [VOCAL Selects SMSC as Its Ethernet Silicon Supplier](https://vocal.com/press-releases/vocal-technologies-selects-smsc-as-its-ethernet-silicon-supplier-for-all-ip-interaction-serving-voice-over-ip-market/) - VOCAL Technologies, Ltd. today announced that VOCAL has selected SMSC’s Ethernet controller for its reference design serving the Voice Over IP market space. - [VOCAL Adds DSP Functionality to MIPS New 32-Bit Pro Series Cores](https://vocal.com/press-releases/dsp-functionality-to-mips-32-bit-pro-series/) - With the MIPS® CorExtend™ Capability, VOCAL Achieves Cryptography Engine on an Industry-Standard Microprocessor. - [VOCAL Quadruples Battery Life in IEEE Wireless LAN Mobile Units](https://vocal.com/press-releases/quadruples-battery-life-in-wlan-mobile-units/) - VOCAL's LDPC and Turbo Code solution quadruples battery life in IEEE 802.11a, 802.11b, and 802.11g Wireless LAN mobile units - [VOCAL LDPC Codes Extend IEEE 802.11a, 802.11b and 802.11g](https://vocal.com/press-releases/ldpc-codes-extend-wlan-range/) - VOCAL's LDPC Software solutions improve power, range, and performance in current and next generation WLANs - [VOCAL Announces HD Video MCU Reference Design](https://vocal.com/press-releases/hd-video-mcu-reference-design-forhd-video-conferencing/) - VOCAL’s HD Video MCU reference design for multi-channel H.264 video conferencing solutions supports wideband audio and up to full HD (1080p) video - [VOCAL Turbo Codes Boost IEEE 802.11a, 802.11b and 802.11g](https://vocal.com/press-releases/vocal-turbo-codes-boost-ieee-802-11a-802-11b-and-802-11g-wireless-lan-performance/) - VOCAL's Turbo Code software boosts performance in current and next generation 802.11 WLANs with low-power transmissions - [VOCAL Technologies Provides Turnkey DSP Software Solution](https://vocal.com/press-releases/turnkey-dsp-solution-to-allworx-10x-server/) - VOCAL's Turnkey Voice Over IP (VoIP) gateway codec system supports 16 channels of realized DSP for InSciTek's Allworx 10x Server - [VOCAL Offers Build-to-Suit IEEE 802.11a, 802.11b, and 802.11g](https://vocal.com/press-releases/build-to-suit-wlan-solution/) - VOCAL offers build-to-suit IEEE 802.11a, 802.11b, and 802.11g Wireless LAN Solutions for custom applications development - [VOCAL Introduces Optimal CTR-AES, CBC-MAC-AES, and CCMP-AES](https://vocal.com/press-releases/ctr-aes-cbc-mac-aes-ccmp-aes-encryption-cores/) - VOCAL Introduces 802.11i Counter mode/CBC-MAC Protocol (CCMP) using AES encryption and message authentication - [Frame Based Maximum Likelihood Classification of Speech](https://vocal.com/voice-quality-enhancement/frame-based-maximum-likelihood-classification-of-speech-and-background-noise/) - The influx of mobile services with its attendant speech-enabled technology has placed speech enhancement algorithms at the forefront of algorithms design. - [VOCAL Creates Unique Solution to Help Transition from Analog to VoIP](https://vocal.com/press-releases/alarm_transition_to_voip/) - VOCAL's AMA and SAMS combine to provide solution for alarm companies dealing with VoIP transitioning. - [Speech Pitch Detection Using Modified Average Magnitude Difference](https://vocal.com/voice-quality-enhancement/speech-pitch-detection-using-modified-average-magnitude-difference-functions/) - The use of average magnitude difference function (AMDF) comes with the problem of double pitch in noisy conditions. - [HD Video Reference Design Lowers Cost of 1080P Videoconferencing](https://vocal.com/press-releases/hd-video-reference-design-low-cost-video-conferencing/) - VOCAL Technologies multi-channel H.264 1080p video reference design with HD audio lowers the cost of high definition videoconferencing - [VOCAL Adds DSP Functionality to MIPS New 32-Bit Pro Series](https://vocal.com/press-releases/vocal-adds-dsp-functionality-to-mips-technologies-new-32-bit-pro-series-cores/) - With the MIPS® CorExtend™ Capability, VOCAL Achieves High-End DSP-Like Performance on an Industry-Standard Microprocessor. - [Video Sharpening with Diagonal Sharpening Control](https://vocal.com/video/video-vertical-horizontal-sharpening-with-diagonal-sharpening-control/) - Diagonal sharpening control reduces extra sharpening in diagonal edges or texture elements from vertical and horizontal sharpening. Call us to learn more! - [Enhanced VoIP Stack Design with Echo Cancellation](https://vocal.com/press-releases/enhanced-voip-stack-design-with-echo-cancellation-for-crisp-clear-speech/) - VOCAL's Enhanced VoIP Stack design with proprietary echo cancellation algorithm for superior speech quality in developer applications - [TSVCIS MELPe Synchronization](https://vocal.com/speech-coders/tsvcis-melpe/tsvcis-melpe-synchronization/) - This TSVCIS specification utilizes cryptography, forward error correction, and synchronization techniques to establish a secure communication channel. - [Thank you for sending your info.](https://vocal.com/thank-you-general-form/) - Thank you for contacting Vocal Technologies. We will do our best to get in touch with you as soon as possible! - [Steganography](https://vocal.com/cryptography/steganography/) - Steganography is the art of hiding sensitive data in media, whether it be text, image, video, or more recently, network. - [Spectrum Subtraction: Implementation](https://vocal.com/spectrum-subtraction-implementation/) - The recovered Spectrum Subtraction signal will be enhanced in some optimization measure compared to the original noisy signal. - [ITU G.711.0 Lossless Codec](https://vocal.com/speech-coders/itu-g-711-0-lossless-codec/) - ITU G.711.0 Lossless Codec is a variable bit rate codec which further compresses the G.711 A-law or mu-law symbols. - [Fullband Information Aiding a Subband Echo Canceller](https://vocal.com/echo-cancellation/fullband-information-aiding-a-subband-echo-cancellersubband-echo-canceller/) - By applying fullband information to the subband process the overall performance of an echo canceller can be improved. - [The Impending Removal of Digital Lines](https://vocal.com/resources/the-impending-removal-of-digital-lines/) - Using VOCAL's SIP Analog Modem Server (SAMS), businesses get the benefits of the SIP infrastructure, without replacing legacy pieces of their systems. - [USAF New Helmet System Open Challenge](https://vocal.com/afwerx/) - The AFWERX team has been engaged by the USAF to find sources for a redesign of the current Fixed Wing helmet for it’s next generation. - [Far Field Direction Of Arrival Estimation](https://vocal.com/beamforming-2/far-field-doa/) - Far field direction of arrival estimation needs a robust voice activity detector (VAD) for the accurate collection of speech statistics. - [Acoustic Beamformer Design](https://vocal.com/beamforming-2/beamformer-design/) - VOCAL's acoustic beamformer software is used with microphone arrays for noise reduction and echo cancellation for superior speech enhancement - [Transmit beamforming and beamtracking](https://vocal.com/5g/transmit-beamforming-beamtracking/) - Transmit beamforming, as shown in Fig. 1, is a widely adopted technique in wireless communications for signal transmission from an array of multiple antennas - [Source localization](https://vocal.com/5g/source-localization/) - Direction-of-arrival estimation is a fundamental problem in array signal processing, which has been widely applied in wireless communications and other areas. - [Hearing: Cocktail Party Problem](https://vocal.com/blind-signal-separation/cocktail-party-problem/) - The cocktail party problem can be described by one simple sentence: How do we recognize what one person is saying when others are speaking at the same time? - [Dynamic Range Compression](https://vocal.com/dynamic-range-compression/) - Dynamic Range Compression (DRC) is part of a Voice Quality Enhancement (VQE) package for both the transmit and receive audio paths. - [PCA: Principal Component Analysis](https://vocal.com/blind-signal-separation/principal-component-analysis/) - Principal Component Analysis, PCA, is similar to ICA but with an interesting underlying assumption that the signal sources are Gaussian. - [Implementation Issues with Subspace Based Estimation Algorithms](https://vocal.com/beamforming-2/implementation-issues-with-subspace-algorithms/) - MUSIC and ESPRIT are considered the two main subspace based estimation algorithms. They both require the theoretical or known correlation matrices. - [FIR Filter Design](https://vocal.com/echo-cancellation/fir-filter-design/) - VOCAL's engineering expertise provides the appropriate FIR Filter Design solution to meet your application performance and resource requirements - [Maximum-Likelihood (ML) Algorithm](https://vocal.com/blind-signal-separation/maximum-likelihood-algorithm/) - The fundamental mathematical tool for parameter estimation is the maximum-likelihood (ML) algorithm. - [Forward Error Correction Algorithms](https://vocal.com/error-correction/) - Forward Error Correction algorithms are optimized for different platforms to meet speed and memory requirements for your application. - [VoIP Technology](https://vocal.com/voip/voip-technology/) - VOCAL provides ITU, GSM, and wideband vocoders including G.721, G.711 PCM μ-law or A-law, G.723, G.726, G.726, and G.728 for customized VoIP solutions - [Tonal Input Suppression Problem](https://vocal.com/echo-cancellation/tonal-input-suppression-problem/) - Tonal input suppression is a well-known problem in acoustic signal processing. VOCAL offers robust approaches to mitigate this problem through various methods. - [H.264/AVC Video Decoder](https://vocal.com/video/h-264avc-video-decoder/) - H.264 video decoding uses interframe and intraframe prediction to recreate the output video signal. Call us to discuss your video application requirements. - [RSA](https://vocal.com/cryptography/rsa/) - RSA is a public-key algorithm used to secure e-commerce and email systems, VPNs, and in security protocols including SSL/TLS, SSH, SET, MIME, PGP, and DNSSEC. - [BCH Error Correcting Codes](https://vocal.com/error-correction/bch-codes/) - Binary BCH codes used in FEC are robust to bursty errors and relatively easy to implement in software and hardware - [Methods of RT60 Estimation](https://vocal.com/dereverberation/methods-of-rt60-estimation/) - For voice enhancement, RT60 is used to characterize reverberation effects in acoustic environments used for audio device verification. Contact us today! - [Signal De-Correlation](https://vocal.com/echo-cancellation/signal-de-correlation/) - Signal de-correlation provides fast convergence for adaptive filters in acoustic echo cancellation and noise reduction solutions. Call us today! - [VPBX Home Gateway Design](https://vocal.com/ata-analog-telephone-adapter/vpbx-home-gateway-unit/) - VOCAL's VPBX Home Gateway design controls and manages all WAN interfaces, LAN and WIFI devices with VoIP and NAT/Firewall support. - [Monaural Speech Separation](https://vocal.com/noise-reduction/monaural-speech-separation/) - VOCALs modular software suite is optimized for leading DSPs to perform Speech Separation/Segregation in conferences and other challenging auditory environments. - [HMAC](https://vocal.com/cryptography/hmac/) - VOCAL's HMAC - Hash Message Authentication Code is available in a wide range of cryptographic solutions for both hardware and software form factors. - [Knowledge enhanced compressive sampling array](https://vocal.com/5g/knowledge-enhanced-compressive-sampling-array/) - According to the compressive sensing theory, the success of compress sensing depends on two essential principles: sparsity and incoherence. - [ESPRIT Algorithm - The Son of MUSIC](https://vocal.com/beamforming-2/esprit-algorithm/) - The MUSIC algorithm has inspired a new elegant extension by utilizing an invariance principle that exists naturally for discrete sequences. - [Beamforming white noise gain](https://vocal.com/beamforming-2/beamforming-white-noise-gain/) - A metric that is used in quantifying the performance of a beamforming algorithm is the is the ability to suppress spatially uncorrelated noise. - [Arithmetic Coding in Vocoders](https://vocal.com/speech-coders/arithmetic-coding/) - Arithmetic Coding uses probability distributions of data values to increase compression rates in Voice Coding. - [ISDN Software](https://vocal.com/telephony-software/isdn-software/) - Digital telephony standards V.110 and V.120 are used in the provision of digital telephone services and systems. - [The FFT: An Efficient Class of Algorithms](https://vocal.com/noise-reduction/fft-algorithms/) - FFTs like Cooley-Tukey algorithm used in noise reduction are very efficient at analyzing the frequency content of a sampled sequence of signal data - [Ringing in Scaling](https://vocal.com/video/ringing-in-scaling/) - Ringing appears during image upscaling in flat or smooth areas near strong edges. Call to discuss your video application requirements. - [Camellia](https://vocal.com/cryptography/camellia/) - VOCAL's optimized Camellia cryptographic algorithm is available in both hardware and software form factors. - [DOFs enhancement using sparse array](https://vocal.com/5g/dofs/) - Direction-of-arrival (DOA) estimation is one fundamental application in array processing, which has been widely used for various fields - [OFDM Modulation](https://vocal.com/video/ofdm-modulation/) - OFDM minimizes intersymbol interference due to multipath propagation in DVB-T systems. Call to discuss your digital video application requirements. - [Whirlpool](https://vocal.com/cryptography/whirlpool/) - VOCAL's wide range of hardware and software cryptographic solutions include Whirlpool hash algorithm - [Broadband Constrained Minimum Variance Beamformer](https://vocal.com/beamforming-2/minimum-variance-beamforming/) - Broadband Constrained Minimum Variance Beamformer provides optimal noise reduction for speech quality enhancement in the most challenging environments - [BSS performance measures](https://vocal.com/beamforming-2/bss-performance-measures/) - Blind source separation (BSS) is a problem that arises when we desire to separate a number of sources from a mixture measurement. Contact VOCAL to learn more. - [Resource Requirements](https://vocal.com/system-designs/resource-requirements/) - VOCAL software libraries are highly optimized for high performance and low memory resource requirements. - [Video PBX Design Specifications](https://vocal.com/ata-analog-telephone-adapter/video-pbx-specifications/) - VOCAL's Video PBX Reference Design supports technical specifications and features to develop a wide range of video products - [Video Description Technology](https://vocal.com/video/video-description-technology/) - Video description technology adds spoken explanations and descriptions to video soundtracks for the blind or visually impaired. Call us to learn more! - [Noise Reduction via Hidden Markov Model (HMM)](https://vocal.com/noise-reduction/noise-reduction-via-hmm/) - HMM-based noise reduction is a powerful alternative to other methods such as spectral subtraction for de-noising speech and source separation. Contact us today! - [Measuring Speech Quality](https://vocal.com/voice-quality-enhancement/measuring-speech-quality/) - Subjective listening tests are preferred, but they are not always feasible and objective tests that attempt to predict - [Tone Detection](https://vocal.com/telephony-software/tone-detection/) - VOCAL's Tone Detection libraries are used world wide in a variety of communications, telephony, signal processing, and radio systems. - [Impulse Noise in TV channels](https://vocal.com/video/impulse-noise-in-tv-channels/) - Impulse noise is a major distortion factor in a TV broadcasting channel. Call us to learn more about video noise reduction for your application! - [Basic Video Scaler](https://vocal.com/video/basic-video-scaler/) - Polyphase filters can be used to scale the input video resolution for output at the specified ratio. Call us to learn more! - [Real-Time Audio Filtering](https://vocal.com/noise-reduction/real-time-audio-filtering/) - Real-Time Filtering of audio signals uses the Overlap-Add Method for block processing convolution of each individual block of samples to maximize performance - [Evaluating Speech Coders](https://vocal.com/speech-coders/evaluating-vocoders/) - Voice coder evaluation must consider round-trip delay, overhead, frame size, look-ahead delays, frame length, MIPS, and memory requirements. - [IEEE 802.11e](https://vocal.com/networking/ieee-802-11e/) - 802.11e defines a set of QoS enhancements for wireless LAN applications through modifications to the MAC layer - [Local Direction Detector](https://vocal.com/video/local-direction-detector/) - Directional interpolators use estimated direction of an edge or texture element for an individual pixel. Call to discuss your video application - [Deinterlacing](https://vocal.com/video/deinterlacing/) - Find out which method to deinterlace video for display on modern video screens is right for your application. Call us today! - [Secure Simple Mail Transport Protocol - SMTP over SSL/TLS](https://vocal.com/secure-communication/secure-smtp-over-ssltls/) - Simple Mail Transport Protocol (SMTP) over SSLv3/TLSv1 uses the STARTTLS extension mechanism to provide secure communications. - [Reed Solomon Implementation](https://vocal.com/error-correction/reed-solomon-implementation/) - VOCAL's Reed Solomon implementation is customizable to work with other RS codes while providing similar performance - [RIPEMD](https://vocal.com/cryptography/ripemd/) - RIPEMD (RACE Integrity Primitives Evaluation Message Digest) is an N-bit message digest algorithm and cryptographic hash function. - [SIP Session Timers](https://vocal.com/sip/session-timers/) - SIP uses session timers for user agents and proxies to determine if a SIP session is still active. (RFC 4028) - [Video Scaling](https://vocal.com/video/video-scaling/) - Video Scaling scales the video output resolution greater than (sometimes 2X or even 4X) the input resolution. Call us to learn more! - [IEEE 802.11n](https://vocal.com/networking/ieee-802-11n/) - IEEE 802.11n uses MIMO technology for improved SNR on the radio link and greater efficiencies in both radio transmissions and MAC protocol - [H.264/AVC Transform](https://vocal.com/video/h-264-avc-transform/) - H.264/AVC transform processes a 16x16 pixel luma macroblock in specific block order. Call today to discuss your video application - [G.168 Test Methodology](https://vocal.com/echo-cancellation/g-168-test-methodology/) - VOCAL’s LEC/NEC software solutions are compliant with ITU G.168-2015 requirements using any of the defined echo path models. Contact us today! - [Single Pixel Camera](https://vocal.com/compressed-sensing/single-pixel-camera/) - A single pixel camera illustrates a physical compressed sensing system where the sampling matrix is created using a digital micromirror device. - [Pixel-Domain Wyner-Ziv Coding](https://vocal.com/video/pixel-domain-wyner-ziv-coding/) - Pixel domain intra-frame video encoder and inter-frame decoder with very low computational encoder complexity. Call us to learn more! - [DVB-T Receiver](https://vocal.com/video/dvb-t-receiver/) - DVB-T receiver converts OFDM-modulated RF signals from a terrestrial TV channel to MPEG transport streams. Call to discuss your video application requirements. - [Tandem Echo Cancellers](https://vocal.com/echo-cancellation/tandem-echo-cancellers/) - Tandem echo cancellers are used in many aspects of networking and voice enhancement. Contact us to learn more! - [Generalized Sidelobe Canceler (GSC)](https://vocal.com/beamforming-2/generalized-sidelobe-canceler-gsc/) - Generalized Sidelobe Canceler can be considered as a special case of Linear constrained Minimum Variance (LCMV) beamforming, one of the earliest in practice. - [IPsec for uClinux](https://vocal.com/networking/ipsec-for-uclinux/) - uClinux is a port of the Linux operating system for embedded systems/microcontrollers without a memory management unit (MMU). - [Pilot Design in FDD massive MIMO](https://vocal.com/5g/mimo/) - In 5G wireless communications, massive MIMO is the most promising technique, which employs a very large number of antennas at the base station. - [ICA: Independent Component Analysis](https://vocal.com/blind-signal-separation/independent-component-analysis/) - ICA, independent component analysis, is one of the first statistic approaches to attempt the cocktail party problem. - [Knowledge enhanced compressive radar ranging](https://vocal.com/5g/compressive-radar-ranging/) - In the era of 5G, faster network connections speed up the development of self-driving cars. The key point to success is high resolution ranging/imaging. - [Knowledge enhanced compressive radar imaging](https://vocal.com/5g/compressive-radar-imaging/) - The incoherence between compressive sensing matrix and signal representation basis guarantees the recovery of sparse signals from sub-Nyquist sampling. - [Acoustic Echoes in Mobile](https://vocal.com/echo-cancellation/acoustic-echoes-in-mobile/) - Direct coupling in mobile devices and acoustic environment in hands-free mode contribute to the acoustic echo path impulse response. Call us to learn more! - [TR-098](https://vocal.com/networking/tr-098/) - TR-098 specifies the Internet Gateway Device data model for managing TR-069 capable devices over a network. Call us to learn more! - [FM Audio Demodulator](https://vocal.com/video/fm-audio-demodulator/) - FM demodulation provides frequency-to-phase conversion for terrestrial analog TV audio signals. Call to discuss your audio video application requirements. - [IEEE 802.11](https://vocal.com/networking/ieee802-11/) - IEEE 802.11 standard provides a Distributed Coordination Function and Authentication and Association - [Blind Source Separation: High Order Statistics Approach](https://vocal.com/blind-signal-separation/blind-source-separation-2/) - High order statistics measures are extensions of second order measures such as autocorrelation and power spectrum. - [Standard Methods of VAD](https://vocal.com/voice-quality-enhancement/standard-methods-of-voice-activity-detection-vad/) - VAD is used for estimating echo and noise and detecting periods of silence in telecommunications and speech processing applications - [Radio](https://vocal.com/resources/reference-designs/radio/) - Our Radio Reference Designs support VoIP radio, soft radio, and radio over IP applications. Contact us today! - [Cryptography](https://vocal.com/cryptography/) - VOCAL's cryptography algorithms use both public and private key methods to provide cryptographic software solutions that ensure telecommunications security - [Compressive sampling array](https://vocal.com/5g/compressive-sampling-array/) - Massive multiple-input multiple-output (MIMO) is regarded as the most significant technique in 5G communications by employing a high number of antennas. - [Blind Source Separation](https://vocal.com/blind-signal-separation/blind-source-separation/) - In this short article, we limit our discussions to algorithms that separate multiple sources or extract information from a linear mix of multiple sources. - [Home PBX Extension Device](https://vocal.com/ata-analog-telephone-adapter/home-pbx-extension-device/) - VOCAL's VPBX Extension Devices (VEDs) are minimal POTS interfaces that extend VoIP access anywhere in an HPNA network. - [Subband Adaptive Filtering](https://vocal.com/echo-cancellation/subband/) - VOCAL's subband adaptive filtering algorithm overcomes limitations of traditional time-domain NLMS implementations of echo cancellation - [Backend Video Processing](https://vocal.com/video/backend-video-processing/) - Back end video processing is an essential part of video processing performed between the video decoder and video monitor. Call us today! - [The Perception of Echo](https://vocal.com/echo-cancellation/perception/) - In telecommunications, there are a couple factors that influence the perception of echoes. The first is the round trip delay. - [Noise Reduction: An Instructional Example](https://vocal.com/noise-reduction/noise-reduction-example/) - Noise reduction example uses Welch's method to estimate noise-only power spectral density and a-priori SNR and soft-decision voice activity detector. - [P2P Network](https://vocal.com/video/p2p-network/) - P2P systems use decentralized communications for robust performance as more nodes are added. Call to discuss your video communications requirements. - [RSA Key Size Selection](https://vocal.com/cryptography/rsa-key-size-selection/) - RSA key size selection must balance computational and security requirements for the data to be protected - [Adaptive Bitrate Streaming](https://vocal.com/video/adaptive-bitrate-streaming/) - ABS monitors user CPU, memory and network performance to manage streaming multimedia. Call to discuss your video streaming application requirements. - [Media Gateway Reference Design](https://vocal.com/system-designs/media-gateway/) - Media Gateway Reference Design supports next-generation video product development with richer features and functionality at lower cost - [TR-104](https://vocal.com/networking/tr-104/) - TR-104 defines the data model for provisioning CPE with voice services by an Auto-Configuration Server (ACS). - [STUN Server in ICE Context](https://vocal.com/networking/stun-server-in-ice-context/) - ICE clients use STUN server capabilities for proper NAT discovery and traversals. Contact us to discuss your network application requirements. - [Video Processing Architecture](https://vocal.com/video/video-processing-architecture/) - Video processing changes the video signal to improve/degrade video quality and to match the communication channel or storage media. Call to learn more! - [Adaptive Null Steering](https://vocal.com/beamforming-2/adaptive-null-steering/) - Microphone arrays can be used to suppress interface sound sources in addition to enhancing a target sound source. - [Mosquito Noise Reduction](https://vocal.com/video/mosquito-noise-reduction/) - Mosquito noise reduction removes artifacts that resemble a checkerboard or single pixel pattern in flat or low level textured areas around strong edges - [Progressive Download](https://vocal.com/video/progressive-download/) - Although widely used for media distribution, progressive download can be inflexible and inefficient. Call to discuss your video streaming requirements. - [Mobile Live Streaming](https://vocal.com/video/mobile-live-streaming/) - Live streaming of video to large numbers of mobile viewers can be challenging. Call to discuss your mobile live streaming application requirements! - [218x Resource Requirements](https://vocal.com/speech-coders/218x-resource-requirements/) - VOCAL software libraries using the Analog Devices 218x platform are optimized for high performance and low memory resource requirements. - [Critical Distance](https://vocal.com/dereverberation/critical-distance/) - Critical distance - distance from the sound source at which the reverberant sound level and the direct signal level are equal for a given frequency - [MELP Modifications to LPC-10](https://vocal.com/speech-coders/melp-modifications/) - MELP speech compression provides superior voice quality at low bandwidths in noisy environments over LPC-10 and other CELP codecs - [Critical Distance and RT60](https://vocal.com/dereverberation/critical-distance-and-rt60/) - RT60 can be used to estimate the critical distance in applications where the early and late reflections influence the reverberation time. Call us today! - [Deep Learning Based Voice-Activity-Detection (DLVAD)](https://vocal.com/blind-signal-separation/dlvad/) - Traditional voice activity detector (VAD) may utilize multiple feature sets based on assumptions on the distribution of speech and noises. - [Noise Models in Testing of Sound Capture Signals](https://vocal.com/audio/noise-models-in-testing-of-sound-capture-signals/) - As microphone array sound capture consists of a desired source signal with additive noise, it is advantageous to be able to approximate noise fields. - [Particle Swarm Optimization in the Design of Adaptive FIR Filters](https://vocal.com/particle-swarm-optimization/adaptive-fir-filters/) - Particle Swarm Optimization provides fast convergence to select Adaptive FIR Filter coefficients for signal processing - [Coherence based interference cancellation through region of arrival](https://vocal.com/beamforming-2/coherence-based-interference-cancellation-through-region-of-arrival/) - Beamforming techniques are highly enhanced based on a-priori knowledge of the noise / interference direction of arrival. - [Application of Psychoacoustic Modeling in Audio Coding](https://vocal.com/audio/application-of-psychoacoustic-modeling-in-audio-coding/) - Psychoacoustic models are used to mask any distortion caused by the quantization process, the effect of quantization is evaluated using psychoacoustic criteria - [Brief Introduction to Ambisonics](https://vocal.com/audio/brief-introduction-to-ambisonics/) - The Kirchhoff-Helmholtz integral equation (KHIE) is used in Ambisonics, a spatial audio technique used to record, reproduce, or simulate a sound field. - [Direction of arrival using uniform circular array microphones](https://vocal.com/beamforming-2/direction-of-arrival-using-uniform-circular-array-microphones/) - The use of uniform circular array UCA microphones for beamforming as an alternative to cascaded quadrilateral topologies. - [Second order adaptive differential microphone array beamforming](https://vocal.com/beamforming-2/second-order-adaptive-differential-microphone-array-beamforming/) - Differential beamforming using three uniform linear array (ULA) microphones, and hence second order, has two different implementations. - [How to get reverberation out of a single microphone recording](https://vocal.com/voice-quality-enhancement/how-to-get-reverberation-out-of-a-single-microphone-recording/) - Reverberation has the effect of degrading both the perception of speech on most quality metrics as well as having adverse effects on (ASR) engines. - [Potential Instability of NE/FE System without Echo Cancellation](https://vocal.com/echo-cancellation/potential-instability-of-nefe-system-without-echo-cancellation/) - Near-End/Far-End systems terminated with either hybrid circuits or acoustic echo paths are potentially unstable. Contact us today! - [Forward Error Correction - Hamming Codes](https://vocal.com/error-correction/forward-error-correction-hamming-codes/) - Applications where the bit error rate is low, but errors cannot be tolerated, Hamming codes provide an computationally efficient encoding and decoding. - [ULA signal to noise plus interference ratio improvements](https://vocal.com/beamforming-2/ula-signal-to-noise-plus-interference-ratio-improvements-with-delay-and-sum-beamformer/) - We derive the expected signal to noise plus interference ratio (SNIR) gains for ULA microphones. Contact VOCAL to learn more about our beamforming solutions. - [Dereverberation Brings the Far-End Speaker Up Close and Clear](https://vocal.com/press-releases/dereverberation-brings-the-far-end-speaker-up-close-and-clear/) - VOCAL's speech dereverberation algorithm removes reverberations while preserving the columns and comb structures of the original voice signal - [Uniform Circular Array Uncorrelated Noise SNR Improvements](https://vocal.com/beamforming-2/uniform-circular-array-uncorrelated-noise-snr-improvements-with-delay-and-sum-beamformer/) - We derive the expected SNR gains for uncorrelated noise on UCA microphones. Contact VOCAL to learn more about our beamforming solutions. - [Speech Dereverberation using Channel Inversion and Equalization](https://vocal.com/dereverberation/speech-dereverberation-using-channel-inversion-and-equalization/) - Speech Dereverberation improves human to human communications and the performance of Automatic Speech Recognition algorithms. Call us today! - [Data Modeling](https://vocal.com/blind-signal-separation/data-modeling/) - In signal processing, we are often given a sequence of sample data and asked to analyze features or patterns of the data sequence. - [Far Field Direction of Sound Source Estimate](https://vocal.com/beamforming-2/far-field-direction-of-sound-source-estimate-using-circular-array-microphones/) - Far field direction of sound source estimate using circular array microphones. Call to discuss your beamforming application requirements. - [Uniform Circular Array Directional Noise SNR Improvements](https://vocal.com/beamforming-2/uniform-circular-array-directional-noise-snr-improvements-with-delay-and-sum-beamformer/) - We derive the expected SNR gains for correlated noise on UCA microphones. Contact VOCAL to learn more. - [First order endfire beamformer uncorrelated noise SNR improvements](https://vocal.com/beamforming-2/first-order-endfire-beamformer-uncorrelated-noise-snr-improvements/) - In absence of anti phase interference, the algorithm should still afford some improvements with regards to uncorrelated noise. Contact VOCAL to learn more. - [Non-conventional Applications of Acoustic Echo Cancellation (AEC)](https://vocal.com/echo-cancellation/non-conventional/) - VOCAL's acoustic echo cancellation solutions are used in VoIP communications, remote monitors, and intercom systems for home, drive-thru, and patient-care - [Voice Activity Detection for Voice Control Applications](https://vocal.com/audio/voice-activity-detection-for-voice-control-applications/) - VOCAL Technologies can offer a custom designed Voice Activity Detect (VAD) solution. Call us to learn more! - [ULA uncorrelated noise SNR improvements with delay and sum beamformer](https://vocal.com/beamforming-2/ula-uncorrelated-noise-snr-improvements-with-delay-and-sum-beamformer/) - Conventional derivations for the signal to noise ratio improvements using delay and sum beamformer is that you get W gain for every doubling of number of mics. - [Speech Enhancement w/ Multi-Mic Noise Reduction in Diffuse Noise Field](https://vocal.com/beamforming-2/multi-mic-speech-enhancement-diffuse-noise/) - MVDR beamforming and GSC are the most popular methods for attenuating coherent interfering noise sources with a determinable direction. - [Two-Path Method for Acoustic Echo Cancellation](https://vocal.com/echo-cancellation/two-path-method/) - A two path filter is used in acoustic echo cancellation to prevent algorithm divergence during double talk detection - [ULA directional noise SNR improvements with delay and sum beamformer](https://vocal.com/beamforming-2/ula-directional-noise-snr-improvements-with-delay-and-sum-beamformer/) - We derive the expected SNR gains for directional gains on ULA microphones. VOCAL Technologies, Ltd. offers beamforming algorithms for any application. - [Speech pitch detection using the magnitude average product function](https://vocal.com/voice-quality-enhancement/speech-pitch-detection-using-the-magnitude-average-product-function/) - Speech pitch detection is a feature with many uses such as speaker diarization and speech activity detector. - [Statistical Joint Control of Acoustic Echo Canceller and Post-Filter](https://vocal.com/echo-cancellation/statistical/) - Joint control of the echo canceller adaptive filter step-size and the post-filter provides improved speech enhancement - [Network Delays and Line / Network Echo Canceller Provisioning](https://vocal.com/echo-cancellation/network-delays-and-line-network-echo-canceller-provisioning/) - Line/Network Echo Cancellers remove echoes at the near end of the network connection for voice quality enhancement for the far-end listener. Call us today! - [The Microphone Array Acoustic Beamforming Compromise](https://vocal.com/beamforming-2/the-microphone-array-acoustic-beamforming-compromise/) - The challenge of wideband acoustic beamforming is the directivity of the microphone array is frequency dependent. - [Scale Invariant Feature Transform (SIFT) for Object Detection](https://vocal.com/video/scale-invariant-feature-transform-sift-for-object-detection/) - Image features extracted by SIFT are stable over image translation, rotation and scaling. Call today to discuss your video application requirements. - [Digital Video Broadcasting for Terrestrial Systems DVB-T](https://vocal.com/video/digital-video-broadcasting-for-terrestrial-systems-dvb-t/) - DVB-T transmits MPEG-2 or MPEG-4 digital audio-video through terrestrial channels. Call to discuss your digital video application requirements - [Secure/Multipurpose Internet Mail Extensions & S/MIME Software](https://vocal.com/secure-communication/smime/) - VOCAL's S/MIME software uses Cryptographic Message Syntax (CMS) to ensure secure communications of messages. - [Schroeder Integration and Reverberation Time](https://vocal.com/resources/schroeder-integration-and-reverberation-time/) - Schroeder's proposed method to calculate reverberation time using backward integration, allows for a more accurate estimation of the reverberation. - [Second order differential linear microphone array beamforming](https://vocal.com/beamforming-2/second-order-differential-linear-microphone-array-beamforming/) - With differential beamformers of 3 or more mics, second order is necessary based purely on the quantity. Call to discuss your beamforming application. - [Efficient Fullband and Wideband AEC Implementations](https://vocal.com/echo-cancellation/efficient-fullband-and-wideband-aec-implementations/) - At VOCAL Technologies, our wideband and fullband AEC is implemented in the subband domain for a variety of embedded DSPs. Please contact us to learn more. - [A and C Weighting via Bilinear Transform and Warping Mitigation](https://vocal.com/a-c-weighting-via-bilinear-transform-warping-mitigation/) - To minimize the nonlinear effect of the bilinear transformation, the input needs to be upsampled and then, after applying the weighting filter, decimated. - [Noise Reduction with Expanded Dynamic Range](https://vocal.com/noise-reduction/noise-reduction-with-expanded-dynamic-range/) - 24-bit audio provides 144dB of dynamic range, allowing for the sound capture of a pin drop to a jet engine without saturating or under representing the signal - [Impulse Response Estimation for Audio via Complementary Sequences](https://vocal.com/echo-cancellation/impulse-response-estimation-via-complementary-sequences/) - Careful engineering of audio devices and acoustic systems requires impulse response estimation to minimize adverse effects of background noise. Call us today! - [Gradient Projection Reconstruction of Compressed Sensing Signals](https://vocal.com/compressed-sensing/gradient-projection-reconstruction/) - A gradient projection algorithm decreases the computational complexity of the compressed sensing reconstruction problem. - [Sound Localization for Helmets Providing Hearing Protection](https://vocal.com/beamforming-2/sound-localization-for-helmets-providing-hearing-protection/) - Use of a helmet with a microphone array to determine the source of a sound through binaural cues, such as level difference (ILD) and time difference (ITD). - [Monaural Cues & Features of Head-Related Transfer Functions](https://vocal.com/audio/monaural-cues-and-features-of-head-related-transfer-functions/) - Monaural cues are essential in vertical localization. These spectral cues cause notches and peaks in the head-related transfer function. - [Two microphone Endfire Beamformer Signal to Noise](https://vocal.com/beamforming-2/two-microphone-endfire-beamformer-signal-to-noise-plus-interferer-improvements/) - We derive the expected signal to noise plus interference ratio (SNIR) gains for the two microphone solution. Contact VOCAL to learn more. - [Concentric Circle Microphone Array Design](https://vocal.com/beamforming-2/concentric-circle-microphone-array-design/) - The design of a microphone array plays an important role in the spatial selectivity of an acoustic beamformer. - [Subband Domain Adaptive Noise Cancellation](https://vocal.com/noise-reduction/subband-domain-adaptive-noise-cancellation/) - subband adaptive filters provide better steady-state convergence for LMS type adaptive algorithms over the fullband implementations with reduced complexity. - [Scalable Joint Distributed Transmit Beamforming And Nullforming](https://vocal.com/beamforming-2/scalable-joint-distributed-transmit-beamforming-and-nullforming/) - Joint distributed transmit beamforming and nullforming is a spatial filtering technique where N cooperative nodes transmit a common message signal to M1 - [Particle Swarm Optimization in the Design of Adaptive IIR Filters](https://vocal.com/particle-swarm-optimization/adaptive-iir-filters/) - Particle Swarm Optimization is used to select Adaptive IIR Filter coefficients for acoustic echo cancellation and other signal processing - [Enhanced Security Based on Under-Determination in Compressed Sensing](https://vocal.com/compressed-sensing/under-determination/) - Under-determination in compressed sensing can be used to enhance security of encrypted messages over standard methods - [Information theoretic approach to single channel dereverberation](https://vocal.com/dereverberation/information-theoretic-approach-to-single-channel-dereverberation/) - The classical acoustic echo canceler assumes there's a reference signal that is being utilized to estimate the acoustic impulse response between a speaker & mic - [Frequency domain single channel blind dereverberation](https://vocal.com/dereverberation/frequency-domain-single-channel-blind-dereverberation/) - The classical acoustic single channel dereverberation assumes that there is a reference signal which is being utilized to estimate the acoustic impulse response - [Adaptive beamforming via steering vector estimation](https://vocal.com/5g/adaptive-beamforming-steering-vector-estimation/) - In the era of 5G, the problem of spectrum congestion has become serious, especially with the popularity of smart devices. - [Near Field Direction of Sound Source Estimate](https://vocal.com/beamforming-2/near-field-direction-of-sound-source-estimate-using-circular-array-microphones/) - Near Field Direction Estimate Using Circular Array. Call to discuss your beamforming application requirements. - [Single Microphone Speech Enhancement Based on Apriori SNR](https://vocal.com/beamforming-2/single-microphone-enhancement-apriori-snr/) - In some real life applications there is only a single microphone being deployed which takes off the table any potential signal to noise ratio (SNR) improvements - [LMS Implementation of First Order Adaptive Differential Beamforming](https://vocal.com/beamforming-2/lms-implementation-of-first-order-adaptive-differential-microphone-array-beamforming/) - In the implementation of first order adaptive differential microphone, the difference between two spatial beams are taking using a scaling parameter. - [Sensitivity of ULA Direction of Arrival Estimates Using GCC Like Algos](https://vocal.com/beamforming-2/sensitivity-of-ula-direction-of-arrival-estimates-using-gcc-like-algorithms/) - GCC like algorithms operating on ULAs are sensitive to the direction of the impinging signals. Please contact us to learn more. - [Exact, Elegant Coherence Based Sub-Band Angle of Arrival](https://vocal.com/beamforming-2/exact-elegant-coherence-based-sub-band-angle-of-arrival-estimation-for-broadband-acoustic-signals/) - The main challenge in all angle of arrival estimation is the uncertainties introduced by either ambient noise or a persistent interfering signal. - [MVDR Based 2 Microphone Beamforming W/ Given Desired Signal Direction](https://vocal.com/beamforming-2/mvdr-based-two-microphone-beamforming-with-given-desired-signal-direction/) - Beamforming solutions for two microphone arrays are highly desirable in applications which require blind source separation with some apriori knowledge - [Full Circle Direction of Arrival Estimation RTOS Using Least Squares](https://vocal.com/beamforming-2/full-circle-direction-of-arrival-estimation-for-rtos-using-least-squares/) - Speech processing on real time operating systems (RTOS) more often than not require estimates of the direction of arrival (DOA). - [Compressed Sensing Approach to Blind Source Separation](https://vocal.com/beamforming-2/compressed-sensing-approach-to-blind-source-separation-of-far-field-sources/) - Because of the inherent sparsity in the assumptions used for blind source separation, compressed sensing may be considered. Please contact VOCAL to learn more. - [SRP-PHAT Angle of Arrival Estimation for Beamforming](https://vocal.com/beamforming-2/finite-set-srp-phat-aoa-estimation-for-beamforming/) - Estimation of the AoA of acoustic signals is essential in acoustic beamforming. There are various research on high resolution algorithms for estimation of AoA. - [Overview of Encryption of Compressed Sensed Images](https://vocal.com/compressed-sensing/encryption-images/) - Signals and images compressed using compressed sensing (CS) are multiplied by a sampling matrix in order to both sample and compress the signal. - [Motion Tracking using Particle Swarm Optimization](https://vocal.com/particle-swarm-optimization/motion-tracking/) - In digital video, motion tracking is the act of continually locating a desired object in video frames over a length of time. - [Delay Tracking for Voice over Packet Switched Network](https://vocal.com/echo-cancellation/delay-tracking-for-voice-over-packet-switched-network/) - Acoustic Echo Cancellation must be performed appropriately in order to achieve the best outcomes. This includes round-trip delay as well as nonlinear distortion - [Psychoacoustic Noise Suppression](https://vocal.com/noise-reduction/psychoacoustic-noise-suppression/) - VOCALs psychoacoustic noise suppression algorithms use physiological and acoustic properties of human hearing to improve the perceptual quality of communication - [Robust fixed point beamforming](https://vocal.com/beamforming-2/robust-fixed-point-beamforming/) - Our algorithms are tuned for minimal performance degradation on customers choice of hardware. Call to discuss your beamforming application requirements. - [Dereverberation and Adaptive Beamforming](https://vocal.com/dereverberation/adaptive-beamforming/) - Modern communications have quickly shifted towards the increased use of hands-free, speakerphone-like systems, such as videoconferencing, laptops and tablets. - [Non-uniform Sampling with Microphone Array](https://vocal.com/beamforming-2/non-uniform-sampling-with-microphone-array/) - Uniform sampling has aliasing problem. It is fairly easy, actually it is more nature to position multiple microphones in a non-uniform or random positions. - [Super directive beamforming with two microphones](https://vocal.com/beamforming-2/super-directive-beamforming-with-two-microphones/) - It is well known that as we increase the number of microphones in any array topology, we increase the signal to noise ratio improvements that can be achieved. - [The Simple Theory of Noise Reduction: Wiener Filtering](https://vocal.com/noise-reduction/the-simple-theory-of-noise-reduction-wiener-filtering/) - Noises are everywhere. The problem of noise reduction can be solved using Wiener Filtering for simple cases. VOCAL offers Wiener and more advanced filtering. - [Adaptive Beam Steering](https://vocal.com/beamforming-2/adaptive-beam-steering/) - A microphone array, if properly designed, has the capability to provide varying gains in different directions in space. - [Keyboard Click Removal](https://vocal.com/noise-reduction/keyboard-click-removal/) - Keyboard Click Removal (KRC) software is designed to suppress the impulsive clicking noise generated by keyboards or mice. - [Fault detection in microphone arrays for speech enhancement](https://vocal.com/beamforming-2/fault-detection-in-microphone-arrays-for-speech-enhancement/) - Microphone array beamforming for speech enhancement and automatic speech recognition is prevalent in many real life application. - [Noise Cancellation Application](https://vocal.com/noise-reduction/noise-cancellation-application/) - Noise cancellation is often implemented in DSP applications using the least mean squared algorithm. A speech signal contaminated with noise may be filtered - [JPEG2000 Rate and Quality Scalability](https://vocal.com/video-codecs/scalability/) - The scalable properties of JPEG2000 are explored including the resoltion scalability and quality scalability. - [Noise Estimation: Dynamics v. Stationarity](https://vocal.com/noise-reduction/noise-estimation-dynamics-v-stationarity/) - Noise estimation can be carried out when the local speech is silent and the frames under consideration contains noise only. - [Binaural Cues in Lateral Localization](https://vocal.com/audio/binaural-cues-in-lateral-localization/) - By sampling the acoustic signal with both ears, the auditory system exploits the differences in captured signal to determine the location of the auditory event - [Unifying Spectrum Subtraction with Wiener Filtering](https://vocal.com/noise-reduction/unifying-spectrum-subtraction-with-wiener-filtering/) - The gain factor representation shows the main conceptual difference between Wiener filtering and spectrum subtraction. - [Voice activity detection with adaptive thresholding](https://vocal.com/voice-quality-enhancement/voice-activity-detection-with-adaptive-thresholding/) - A voice activity detector is utilized, not only to limit robust processing only during actual speech frames, but also to dynamically detect the noise floor. - [Angle of Arrival Voice Activity Detection](https://vocal.com/beamforming-2/angle-of-arrival-voice-activity-detection/) - VOCALs AoA Voice Activity Detection (VAD) software uses multiple input signals from a mic array to determine if there is active speech in a specified direction. - [Speech pitch detection using the average magnitude difference function](https://vocal.com/voice-quality-enhancement/speech-pitch-detection-using-the-average-magnitude-difference-function/) - The most used pitch detection algorithm for real time operating systems is the average magnitude difference function due to is low computational complexity. - [Second order digital equalizers](https://vocal.com/voice-quality-enhancement/second-order-digital-equalizers/) - Second order equalizers can be used for real time signal enhancement procedures to improve speech quality adjusting the magnitude responses of frequencies. - [Perceptual-Based Spectrum Subtraction Noise Reduction](https://vocal.com/noise-reduction/perceptual-based-spectrum-subtraction-noise-reduction/) - VOCAL Technologies offers noise reduction solutions to combat noise masking, noise signals that are too close in frequency or time - [Secure JPEG2000 (JPSEC) Images](https://vocal.com/video-codecs/jpsec/) - PEG2000 Is an image compression scheme based on the discrete wavelet transform (DWT) and embedded block coding with optimal truncation (EBCOT) scalable coding. - [Voice-Activity-Detection (VAD) Feature Set](https://vocal.com/noise-reduction/voice-activity-detection-vad-feature-set/) - Many features have been used successfully for VAD detection in practice. VOCAL technologies Acoustic Library provides robust and reliable VAD modules - [Voice activity detection with spectral flux](https://vocal.com/voice-quality-enhancement/voice-activity-detection-with-spectral-flux/) - Voice activity detectors always discriminate between features of speech and noise. The spectral flux approach is used to produce a decision rule - [Voice activity detection with long term spectral divergence](https://vocal.com/voice-quality-enhancement/voice-activity-detection-with-long-term-spectral-divergence/) - Voice activity detectors are designed to discriminate between features of speech and noise using long term spectral divergence to produce a decision rule. - [Blind Signal Separation (BSS) using Particle Swarm Optimization (PSO)](https://vocal.com/particle-swarm-optimization/blind-signal-separation-with-pso/) - BSS consists of techniques for doing this without prior knowledge of either the signals or the way in which they are mixed. - [Frequency modulation detection for speech](https://vocal.com/voice-quality-enhancement/frequency-modulation-detection-for-speech/) - Frequency modulation (FM) as a computational auditory scene analysis feature refers to the phoneme changes in audio streams. - [Amplitude modulation spectrum detection for speech](https://vocal.com/voice-quality-enhancement/amplitude-modulation-spectrum-detection-for-speech/) - AMS for speech separation is motivated by observations that variations in modulation frequency provides a long term window for characterizing speech information - [Adaptive voice activity detection using time domain zero crossings](https://vocal.com/voice-quality-enhancement/adaptive-voice-activity-detection-using-time-domain-zero-crossings/) - A voice activity detector (VAD) is utilized not only to limit robust processing only during actual speech frames, but also to dynamically detect the noise floor - [First order derivative to detect speech onset and offset](https://vocal.com/voice-quality-enhancement/first-order-derivative-to-detect-speech-onset-and-offset/) - A standard approach is to use a first order derivative of the sound pressure level with respect to time. - [Two microphone source separation with spatial prior](https://vocal.com/beamforming-2/two-microphone-source-separation-with-spatial-prior/) - In a scenario where prior knowledge of the direction of the desired source is known, this information can further be used to suppress undesired noise and speech - [Spatial Sampling and Aliasing with Microphone Array](https://vocal.com/echo-cancellation/spatial-sampling-and-aliasing-with-microphone-array/) - Microphone arrays measure sound waves in both time and space. Microphone arrays make possible the exploration of the spatial features of a sound wave. - [Adapting Particle Swarm Optimization with State of Convergence](https://vocal.com/particle-swarm-optimization/state-of-convergence/) - An algorithm is presented for deciding on the state of convergence of PSO and, based on this, adapting its parameters apropriately. - [Automatic Volume Control](https://vocal.com/voice-quality-enhancement/automatic-volume-control/) - Automatic Volume Control software applies a frequency dependent amplitude modification to the received signal prior to being sent to the loudspeaker. - [Multi-Mic Wiener Noise Suppression](https://vocal.com/beamforming-2/multi-mic-audio-signal-processing/multi-mic-wiener-noise-suppression/) - Multi-mic noise estimation can be used to aid single channel noise estimation required for Wiener Noise Suppression - [Second order differential non-linear microphone array beamforming](https://vocal.com/beamforming-2/second-order-differential-non-linear-microphone-array-beamforming/) - Second Order Differential Microphone Array Beamforming. With differential beamformers of 3 or more mics, second order is necessary based purely on the quantity. - [Noise Cancellation Microphones for Automatic Speech Recognition](https://vocal.com/voice-quality-enhancement/noise-cancellation-microphones-for-automatic-speech-recognition/) - Dual Channel Adaptive Noise Reduction algo is well suited as a pre-processor for ASR engines because the noise reduction is achieved through a linear process. - [Noise Cancellation Microphones](https://vocal.com/voice-quality-enhancement/noise-cancellation-microphones/) - VOCAL’s Microphone Adaptive Noise Cancellation Software can remove additive noise even when the signal to noise ratio (SNR) is very low, about 0 dB. - [VOCAL Technologies Chooses Legerity VoicePort for Ultra Low Cost ATA](https://vocal.com/press-releases/vocal-technologies-chooses-legerity-voiceport-for-ultra-low-cost-ata/) - VOCAL Technologies announced a compact, configurable analog telephone adapter (ATA) hardware and software reference design platform. - [Maximum Likelihood Voice Activity Detector](https://vocal.com/voice-quality-enhancement/maximum-likelihood-voice-activity-detector/) - In almost all online sound signal processing, a voice activity detector, VAD, is utilized to limit the the use of the expensive computational time. - [Voice Activity Detectors and Their Applications](https://vocal.com/voice-quality-enhancement/voice-activity-detectors-and-their-applications/) - VADs are used in echo cancellers, noise reduction algorithms, and speech coders. In this article we will give a brief summary of the role VADs plays. - [Residual echo suppression](https://vocal.com/echo-cancellation/residual-echo-suppression/) - Real time implementations utilize finite impulse responses (FIR) to cancel out far end echo signals in wireless devices. - [Acoustic Echo Cancellation for Wireless Devices](https://vocal.com/echo-cancellation/acoustic-echo-cancellation-for-wireless-devices/) - Standard AEC software can be applied in mobile devices to remove echoes causes by the acoustic coupling between the loudspeaker and microphone. - [An Algorithm to Monitor Available Bandwidth for Video Streams](https://vocal.com/resources/research/video-research/an-algorithm-to-monitor-available-bandwidth-for-video-streams/) - This article presents an algorithm that can give a rough estimate of how much network bandwidth is available for the video stream. - [Estimating Compressed Bitrate Requirements for Video Streams](https://vocal.com/resources/research/video-research/estimating-compressed-bitrate-requirements-for-video-streams/) - Streaming video over a network requires video compression to reduce the bandwidth requirements, & the video encoder is usually configured with a bitrate setting - [Maximum likelihood classification of speech and background noise](https://vocal.com/voice-quality-enhancement/maximum-likelihood-classification-of-speech-and-background-noise/) - The most fundamental tasks of all speech enhancement algorithms is the ability to discriminate between speech and noise and suppress noise as much as possible. - [Acoustic echo cancellation with the LMS algorithm](https://vocal.com/beamforming-2/acoustic-echo-cancellation-with-the-lms-algorithm/) - The presence of AES can degrade the quality of a signal significantly hence the vast interest in acoustic echo cancellation (AEC) algorithms. - [Acoustic echo cancellation with the ML algorithm](https://vocal.com/beamforming-2/acoustic-echo-cancellation-with-the-ml-algorithm/) - Typical algorithms for acoustic echo cancellation (AEC) are the LMS and NLMS algorithms for their ease of implementation and relatively fast convergence rates. - [Effective filter for diamond array microphones](https://vocal.com/beamforming-2/effective-filter-for-diamond-array-microphones/) - Effective Filter for Diamond Array Microphones. Call to discuss your beamforming application requirements. - [Spectral subtraction of acoustic noise](https://vocal.com/beamforming-2/spectral-subtraction-of-acoustic-noise/) - One of the main challenges in beamforming is how to isolate unwanted signals and attenuate them as much as possible. - [Fast beamformer with fixed direction for circular array microphones](https://vocal.com/beamforming-2/fast-beamformer-with-fixed-direction-for-circular-array-microphones/) - We show an approach to beamforming an acoustic source using a circular microphone topology. Consider the circular array illustrated in Figure 1 below. - [Link Quality Indicators for Detection of Interfering Signals](https://vocal.com/beamforming-2/link-quality-indicators/) - Link quality indicators (LQI) are proprietary numbers that give an indication of how good a communication channel is for transmission & correct reception. - [Full plane least squares acoustic sound source localization](https://vocal.com/beamforming-2/full-plane-least-squares-acoustic-sound-source-localization/) - The need to pinpoint the exact originating point of acoustic sources is gaining traction for applications such as gaming and conferencing. - [Efficient distortionless response for conferencing](https://vocal.com/beamforming-2/efficient-distortionless-response-for-conferencing/) - Least variance distortionless response is well known for delivering extremely good results in terms of SNR improvements. - [ATA Compatibility and Interoperability](https://vocal.com/ata-analog-telephone-adapter/compatibility-and-interoperability/) - VOCAL's field proven standards based Analog Telephone Adapter software is thoroughly tested for compatiblity and interoperablity with other vendors - [Basic Video Sharpening](https://vocal.com/video/basic-video-sharpening/) - Video Sharpening is used to enhance subjective output video quality. Call us to learn more about meeting your application requirements - [Minimum Variance Distortionless Response Beamformer Software](https://vocal.com/beamforming-2/mvdr-beamformer/) - MVDR beamformer for speech enhancement, noise reduction, and speech dereverberation maintains a distortionless mainlobe response toward the desired signal - [Secure Faxing with JPSEC](https://vocal.com/fax-modem/secure-faxing-with-jpsec/) - Secure JPEG 2000 (JPSEC) provides stronger encryption and data integrity for Fax documents than T.30. - [Video Surveillance Technology](https://vocal.com/video/video-surveillance-technology/) - CCTV is used to monitor a particular area for people, vehicles and hazardous conditions. Call to discuss your video surveillance application requirements. - [Analog TV Standards](https://vocal.com/video/analog-tv-standards/) - VOCAL designs innovative video solutions using NTSC, PAL, SECAM and other standards. Call us to discuss your video application requirements! - [TCP TURN](https://vocal.com/networking/tcp-turn/) - TCP TURN offers enhanced communication security. Call to discuss your network application security requirements - [Constant Beamwidth Frequency Domain Broadband Beamformer](https://vocal.com/beamforming-2/frequency-domain-beamformer/) - Constant Beamwidth Frequency Domain Broadband Beamformer software provides constant spatial discrimination performance across the full frequency band - [Analog TV Demodulation](https://vocal.com/video/analog-tv-demodulation/) - DSP enables a common approach to demodulating video signals for the different standards. 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