A new adaptive digital echo canceller

A composition of the newly developed adaptive digital echo canceller is proposed. This is used with hands-free phone of cellular mobile radio telephone equipment. The transfer function of the adaptive digital filter is composed of the zero-point function (FIR) and the pole function (IIR). The adaptive digital filter is adopted which is previously developed for the IIR filter and for which the sequential stability is ensured. It is confirmed by the computer simulation that the adaptive digital filter requires nearly 1/5 in the number of taps compared with that of conventional transversal filter for the same echo path model. According to the results of computer simulation, the performances of the proposed echo canceller are shown.