SYSTEM FOR CODING SPEECH INFORMATION USING AN ADAPTIVE CODEBOOK WITH ENHANCED VARIABLE RESOLUTION SCHEME

摘要

A speech coding system includes an adaptive codebook containing excitation vector data associated with corresponding adaptive codebook indices (e.g., pitch lags). Different excitation vectors in the adaptive codebook have distinct corresponding resolution levels. The resolution levels include a first resolution range of continously variable or finely variable resolution levels. Again adjuster scales a selected excitation vector data or preferential excitation vector data from the adaptive codebook. A synthesis filter synthesizes a synthesized speech signal in response to an input of the scaled excitation vector data. The speech coding system may be applied to an encoder, a decoder, or both.