Adaptive echo cancellation techniques are presently used to implement hands free telephone sets. The LMS-algorithm, or least-mean-square algorithm, represents the most common adaption technique for acoustic echo control [1].
The use of maximum-length sequences, also called m-sequences, to determine the impulse response of a particular electro-acoustic transmission system is well known in applications such as acoustic irradiation systems [2]. Furthermore, for m-sequences the Fast Hadamard Transformation can be applied to minimize the computational complexity [3].
In this contribution a combined implementation of an echo compensator exploiting mismatched filter techniques and the conventional LMS-algorithm is proposed. The corresponding model is illustrated in Fig. 1.