Patent ID: 8306214
Filing Date: 2012-11-06
Classification: G10L,H04M

Abstract:
1. A method of residual echo reduction which follows an acoustic echo cancellation (AEC) wherein a microphone signal resulting from an unobservable signal corrupted by an acoustic echo is processed in an attempt to restore the unobservable signal, the acoustic echo being a speaker signal modified by an acoustic path, wherein an adaptive filter models the echo path in the frequency domain, the adaptive filter is applied to the speaker signal to produce an echo signal that models the acoustic echo, and the echo signal is subtracted from the microphone signal to produce an output signal that resembles the unobservable signal but includes a residual echo, the method comprising: receiving the AEC output signal which still contains the residual echo as a target signal; receiving the microphone signal; applying an adaptive residual echo filter to the microphone signal; subtracting the adaptive residual echo filter output signal from the target signal to determine an error signal; adapting the adaptive residual echo filter based on the error signal; and applying a copy of the adaptive residual echo filter to the AEC output signal to remove any residual echo.