Patent ID: 6044068
Filing Date: 2000-03-28
Classification: H04B

Abstract:
A line echo cancellation method comprising:sampling a signal on an incoming communications path to obtain a sample at time t(m);determining whether a window W(m) of samples contains silence, the window W(m) including the sample obtained at the time t(m) and prior samples, and if the window W(m) contains silence, then setting coefficients of an adaptive filter of an echo canceller at silence detection values prior to receipt of a sample at time t(m+1); otherwise,using the sample obtained at time t(m) to update coefficients of an adaptive filter, using the adaptive filter as updated to generate an echo estimate after a sample is obtained at time t(m+1), and using the echo estimate to modify a signal on an outgoing communications path;wherein a time duration of window W(m) is longer than an echo path pure delay and wherein, in determining the timing of the silence-affected period on an outgoing communication path;at an end of a first instance of a window W(s) having the silence detected throughout its duration, the silence-affected period is commenced, andupon cessation of the silence in the signal on the incoming communication path, the silence-affected period is terminated.