Systems and methods for stereo echo cancellation

摘要

Acoustic echoes in communications systems are distracting and undesirable. Acoustic echoes occur in communications systems where sound produced by a speaker is picked up by a microphone in a communications system. In a stereo playback environment, echo cancellation techniques become more complicated. Echo cancellation can be performed by performing echo cancellation on a center signal, which is the sum of a left channel signal and the right channel signal, or left signal and a difference signal, which is the difference of the right channel signal and the left channel signal. The adaptation rates of the two echo cancellers meet certain constraints to prevent degeneracies in the echo cancellation system.

主权项

1. A method of cancelling an echo comprising:
generating a difference signal by subtracting a first far-end signal from a second far-end signal; generating a first echo cancellation signal by applying a first adaptive filter to only the first of the far-end signals; generating a difference echo cancellation signal by applying a difference adaptive filter to the difference signal; subtracting the first echo cancellation signal from a received signal; subtracting the difference echo cancellation signal from the received signal; updating the first adaptive filter at a first adaptation rate; and updating the difference adaptive filter at a second adaptation rate, where the first adaptation rate is different from the second adaptation rate.