Multistage echo canceller including time variation compensation

摘要: Acoustic echos are canceled by employing a first echo canceler having comparatively long impulse response synthesis capability which is connected between transmit path and receive for generating error signal canceling signals in the path, at least second short parallel with path. The supplied from adaptively operating simultaneously but independent of to further cancel Specifically, intended capture substantially stationary any slowly varying components response, more time varying, i.e., dynamically component response. I have recognized that certain applications, may exist relatively interval. For instance, acoustic echos, most variation results movement objects and/or persons near either microphone or loudspeaker. This significant changes early portion Aligning tap coefficients this provides significantly enhanced cancelation performance over achievable only canceler. realized placing "short" fixed delay series In other still exists interval, relative overall change not be known priori. Under these circumstances, it desirable align adjustable one embodiment, value generated coefficient values