ECHO CANCELLER EMPLOYING DUAL-H ARCHITECTURE HAVING SPLIT ADAPTIVE GAIN SETTINGS

摘要

An echo canceller circuit (25) is set forth. The echo canceller circuit (25) includes a digital filter (30) having adaptive tap coefficients to simulate an echo response occurring during a call. The adaptive tap coefficients are updated during the call using a Mean Squares process. A tap energy detector is also employed. The tap energy detector identifies and divides groups of taps having high energy from groups of taps having low energy. The high energy tap groups are larger in number than the low energy tap groups. The high energy tap groups are adapted separately from the low energy tap groups using the Least Squares process. Still further, the high energy tap groups may be adapted using an adaptive gain constant a while the low adaptive energy tap groups are adapted using an adaptive gain constant a', wherein a > a'.