Patent ID: 6944289

Claim:
A method for delay insertion for echo cancellation for communication in a selected frequency spectrum, the echo cancellation having a predetermined time period capacity, the method comprising: (a) down sampling, by a down sampling factor, a spectral portion of a reference signal and a spectral portion of a combined signal to form, respectively, a down sampled reference signal and a down sampled combined signal, wherein the combined signal includes an echo of the reference signal; (b) determining a plurality of filter coefficients using a feedback signal formed as a difference between an adaptive echo delay filter output and the down sampled combined signal, each filter coefficient of the plurality of filter coefficients having a filter location; (c) when the plurality of filter coefficients have converged, determining a maximum filter coefficient of the plurality of filter coefficients and determining a corresponding maximum coefficient filter location; (d) determining an echo delay time period as a product of the corresponding maximum coefficient filter location and the down sampling factor; and (e) when the echo delay time period is greater than the predetermined time period capacity for echo cancellation, inserting the echo delay time period prior to echo cancellation.