Patent ID: 6580794
Filing Date: 2003-06-17
Classification: H04M

Abstract:
An acoustic echo canceler for a speech communication system including a loudspeaker and a microphone acoustically coupled with the loudspeaker through a feedback path, comprising:an adaptive filter including a tapped delay line for receiving a remote speech signal to produce a sequence of successively delayed tap signals and a convolutional integrator for respectively weighting the tap signals with filter coefficients and summing the weighted tap signals to produce an acoustic echo replica of said remote speech signal, and updating said filter coefficients with a residual echo; said adaptive filter further including a detector for detecting a peak impulse response of said feedback path corresponding to an echo component of said remote speech signal, a first selector for restricting the filter coefficients to those which correspond to said echo component and a second selector for restricting the tap signals to those which correspond to the restricted filter coefficients; a subtractor for combining an output signal of the microphone with said acoustic echo replica to produce said residual echo; an attenuator for receiving an output signal of said subtractor; and comparator circuitry for comparing the output signal of the subtractor with the restricted tap signals of the adaptive filter, increasing the attenuation of the attenuator when the restricted tap signals are greater in magnitude than the output signal of the subtractor, and decreasing said attenuation when the restricted tap signals are smaller in magnitude than the output signal of the subtractor.