Echo Cancellation

Echo Cancellation is used to enhance speech for Radio, Mobile, VoIP and Voice applications

VOCAL offers a range of echo cancellation solutions including:


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.

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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.

acoustic echo cancellation Echo Cancellation

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.

line network echo canceller Echo Cancellation

AEC Barge-In

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. 

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Operating Systems

  • 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
  • Symbian
  • Wind River VxWorks