Patent ID: 7003101

Claim:
A method of effecting echo cancellation in a communications channel, comprising: receiving an input signal containing an echo signal; developing an estimate signal of said echo signal with a fullband adaptive filter having a plurality of updatable coefficients; subbanding said received input signal into a single subband; identifying echo locations within said subband with a subband adaptive filter having coefficients; and updating a limited set of coefficients in said fullband adaptive filter as determined by said echo locations identified in said single subband by said subband filter; and subtracting said estimate signal from an output signal coupled to said input signal; and wherein said subband adaptive filter generates an echo replica which is subtracted from said output signal to generate an error signal; said error signal updates the coefficients of said subband adaptive filter; and said echo locations are determined by analyzing the absolute values of said coefficients of said subband filter to identify the peaks in said absolute values.