An acoustic echo canceler (10) includes an adaptive filter circuit (12) and a near-end speech detection circuit (14). The adaptive filter circuit (12) includes an adaptive filter that may be of a single or dual filter structure for generating an e(t) acoustic echo canceler output signal (26) in response...http://www.google.de/patents/US5633936?utm_source=gb-gplus-sharePatent US5633936 - Method and apparatus for detecting a near-end speech signal
