Echo Cancellation is used to enhance speech for Radio, Mobile, VoIP and Voice applications. Whether the echo is electrical, acoustical, or has multiple sources, VOCAL has developed the solution for it. Full-duplex voice communication systems require an echo cancellation solution for clear and effective conversations. Echo cancellation software must have fast convergence speeds, resilient double-talk performance, and robustness to background noise. VOCAL’s solutions offer this and much more.
VOCAL offers a range of echo cancellation solutions including:
- Acoustic Echo Cancellers (AEC)
- Line / Network Echo Cancellers (LEC / NEC)
- Stereo and Multichannel Acoustic Echo Cancellers
- Efficient Fullband Acoustic Echo Cancellers
- AEC Barge-In
- Custom Echo Cancellation
We have extensive experience in the development, integration, and configuration of echo cancellation solutions in a wide variety of products. Contact us to discuss your echo cancellation application requirements.
Echo Cancellation is the reduction of the reflected copies of a direct path wave in a signal. In telephony, the source of these reflections can be generated electrically due to an impedance mismatch in the transmission path or as a result of an acoustic and/or mechanical coupling between a loudspeaker and a microphone, usually because they are in the same physical enclosure. For acoustic/mechanical coupling an Acoustic Echo Canceller (AEC) is required; whereas, a Line Echo Canceller (LEC) is used to address impedance mismatch.
Acoustic Echo Cancellation
Acoustic Echo Cancellation is an essential part of providing speech enhancement (or voice quality enhancement) to any telephone communication. An acoustic echo canceller (AEC) operates on the digitally sampled audio signals of the communication device. The transfer function of the acoustic environment from the loudspeaker to the microphone on the device is estimated to cancel the received echoes from the microphone signal.
Line/Network Echo Cancellation
Line/Network Echo Cancellation uses voice activated devices placed in the 4-wire portion of a circuit (which may be an individual circuit path or a path carrying a multiplexed signal) and are used for reducing the echo by subtracting an estimation from the circuit echo. They may be characterized by whether the transmission path or the subtraction of the echo is by analogue or digital means.
Stereo and Multichannel AEC
For full-duplex audio devices that contains more than one loudspeaker or more than one microphone, VOCAL’s Multichannel AEC software can be applied to achieve the optimal echo cancellation performance. The AEC software can be configured to support any number of loudspeakers and microphones. This software is ideal for AV conferencing units, sound bars, stereo headsets.
Fullband Acoustic Echo Cancellation
VOCAL’s AEC is available for fullband sampling rates up to 96kHz. The structure of the AEC software allows for computationally efficient echo cancellation without the need for downsampling. This is ideal for professional audio applications. For even further fidelity, interfaces supporting 24-bit sample data are available upon request.
The application of AEC for barge-in is different than standard full-duplex communication applications. Wake Word Detection (WWD) and Automatic Speech Recognition (ASR) software does not tolerate non-linear distortions to the near-end speech trying to be detected in the presence of constantly strong echo. VOCAL’s AEC software can be configured to serve as a pre-processor to the WWD & ASR software.
Custom Echo Cancellation
In our 30+ years of experience of digital signal processing, we have seen many situations and products, where standard (and especially open source) echo cancellation solutions are not able to properly remove the echo. Whether the cause of the failure is from poor mechanical design, or asynchronous transmit and receive paths, our custom echo cancellation solutions will provide you the best design for your product development. We also offer custom offline echo cancellers too.
AEC with VQE Suite
VOCAL’s Acoustic Echo Cancellation software can be combined with VOCAL’s other Voice Quality Enhancement (VQE) software to provide a complete . VQE suite can include multi-microphone and single microphone noise reduction, microphone array beamforming, automatic gain control, multi-band dynamic range compression, and more!
AEC with VOCAL’s V2oIP Stack
VOCAL’s Acoustic Echo Cancellation software is available as part of our Voice and Video over IP (V2oIP) stack for an end-to-end full duplex voice communication solution.
- Texas Instruments – C6xx (TMS320C62x, TMS320C64x, TMS320C645x, TMS320C66x, TMS320C67x), DaVinci, OMAP, C5xx (TMS320C54x, TMS320C55x)
- Analog Devices – Blackfin, ADSP-21xx, TigerSHARC, SHARC
- PowerPC, PowerQUICC
- MIPS – MIPS32, MIPS64, MIPS4Kc
- ARM – ARM7, ARM9, ARM9E, ARM10E, ARM11, StrongARM, ARMCortex-A8/A9/A15/A3x/A5x/A7x, Cortex-M3/M4
- Intel / AMD – x86, x64 (both 32 and 64 bit modes)
- Linux, uClinux, BSD, Unix
- Microsoft Windows ACM / RTC / CE / Mobile
- Apple iOS / iPhone / iPad & MacOS
- eCOS / eCOSPro
- Google Android
- Green Hills Integrity
- Micrium μCOS
- Wind River VxWorks
- VOCAL LANsEND