Echo canceller employing dual-H architecture having split...

Details Echo canceller employing dual-H architecture having split... Echo canceller employing dual-H architecture having split...

2004-02-17

2008-07-22

Singh, Ramnandan (Department: 2614)

Telephonic communications

Echo cancellation or suppression

C379S406060

Reexamination Certificate

active

07403610

ABSTRACT:
An echo canceller circuit is set forth. The echo canceller circuit includes a digital filter having adaptive tap coefficients to simulate an echo response occurring during a call. The adaptive tap coefficients are updated during the call using a Means 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 smaller 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 α while the low energy tap groups are adapted using an adaptive gain constant α′, wherein α>α′.

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