Enhancement of block-coded speech

This paper describes a very effective method for reducing framing noise associated with block-by-block speech coding algorithms. It is a post-coding speech enhancement procedure designed specifically to combat this type of noise. The procedure is based on a fully adaptive comb filter which is adapted in synchrony with the coding algorithm´s frame boundary. An optimal (minimum mean-squared-error sense) linear prediction approach is applied to determine the filter coefficients and adapt them to the short-time statistics of the speech. A formal subjective listening trial has shown the method to significantly improve the perceived quality of block-coded speech.