Study of a pole - zero adaptive echo canceller

The performance of a pole-zero adaptive filter in echo cancellation is studied. Compared with conventional transversal filters, this structure requires fewer taps to achieve the same echo cancellation performance when the echo path can be well modeled by a rational transfer function. Such issues as the degree of echo cancellation, the stability of the filter, the selection of the order, and the effects of observation noise are studied by using simulated echo path models and then tested with actual measured acoustic echo models in teleconferencing. The advantages and remaining problems are discussed.