A simple method of broad band speech recovery from narrow band speech for quality enhancement

This paper describes a 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 new method that offers improved performance in terms of spectrum distortion characteristics. Implementation procedures are clarified, and its performance is discussed. The proposed method can effectively enhance speech quality.