Patent ID: 6751314
Filing Date: 2004-06-15
Classification: H04B

Abstract:
An improved method for canceling an echo of a far end speech signal, comprising the steps of:periodically sampling said far end speech signal; at sampling instant n=0 and thereafter at sampling instants n mod M=0, where M is a predetermined number of samples, determining L multiplying coefficients corresponding to the entire duration of the echo path impulse response; performing a convolution of the far end sampled speech signal over the L coefficients, resulting in an estimate of said echo, calculating the error, if any, between said echo and said estimate of said echo; adapting said L coefficients to reduce any error between said echo and said estimate of said echo, and determining from said L coefficients a set of La coefficients corresponding to the active region of said echo impulse response, wherein Laat each sampling instant nâ‰ 0 and n mod Mâ‰ 0, performing a convolution of the far end speech signal over the La coefficients, resulting in an estimate of said echo; calculating the error, if any, between said echo and said estimate of said echo; and adapting said La coefficients to reduce any error between said echo impulse response and said estimate of said echo impulse response only if the magnitude of said error is greater than a given error threshold.