Signal restoration of broad band speech using nonlinear processing

This paper describes a new system that can enhance the quality of speech signals that have been severely band limited during transmission. We have already proposed a spectrum widening method that utilizes aliasing in sampling rate conversion with digital filtering for spectrum shaping. This paper proposes a quite simple method by adding spectrum in the higher band using nonlinear processing. Implementation procedures are clarified, and its performance is discussed. It is shown that the proposed method offers good performance in terms of spectrum distortion characteristics.