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acoustic echo cancellation (AEC)

Acoustic Echo Cancellation (AEC) is a method of compensating for echoes, reverberation and disturbing noises in acoustic signals. The AEC method removes

disturbing influences that occur in a room from audio signals. Electronic circuits are available for acoustic echo cancellation, which compensate for echoes, reverberation and other acoustic disturbances in the audio signal and prevent them from reaching the receiver. Without echo cancellation, an unnatural sound would result and the interference would significantly impair speech intelligibility

.Conceptually, AEC circuits consist of a signal path through which a person's speech signal is transmitted to the loudspeaker

.

The loudspeaker signal, which reflects off the walls of the room, is picked up by a microphone and transmitted via the second signal path. Both signal paths - the one to the loudspeaker and the one from the microphone - are interconnected by an Adaptive FIR Filter, whose algorithm continuously adapts the filter

to the acoustic conditions. The Adaptive FIR Filter is the core component of the AEC circuit. The noise signal

detected by the FIR is subtracted from the audio signal to compensate for the interference. The implementations for acoustic echo cancellation are optimized for speech.

The bandwidth standard is narrowband with a bandwidth of 4 kHz and a sampling rate of 8 kHz, wideband with a bandwidth of 8 kHz and a sampling rate of 16 kHz, and ultra-wideband with a bandwidth of 16 kHz and a sampling rate of 32 kHz. AEC technology is used in voice communication and hands-free devices.

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Englisch: acoustic echo cancellation - AEC
Updated at: 14.09.2019
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