Acoustic echo cancelation (AEC) composes a fundamental property of speech processing to enable a pleasant telecommunication conversation. Without this property of the telephone the communicator would hear an annoying echo of his own voice along with the speech from the other communicator. This would make a conversation through any telecommunication device an unpleasant experience. With the advent of low cost hands free communication devices the issue of nonlinear echo became prominent because these devices use cheap loudspeakers that produce annoying sound in addition to the desired sound which will cause nonlinear echo that cannot be cancelled by linear echo cancellers. In this paper a Harmonic Distortion Residual Echo Cancelation algorithm has been chosen for further investigations (HDRES). The results show that it may be possible to use an adaptive filter, which has both low complexity and fast convergence, in an operating AEC system. However, the request for such a system to work would be that a doubletalk detector is implemented along with the adaptive algorithm. That way the doubletalk situation could be found and the adaptation of the algorithm could be stopped. Thus, the major part of the speech would be saved.
