A voiced/unvoiced classified vector quantized speech transform coder implemented on a TMS 32020 signal processor

A wideband speech transform coder with embedded classified vector quantization is described. This coder has been implemented on the TMS 32020 digital signal processor. A product code structure is combined with dynamic codebook choice. Classification is carried out with respect to voiced/unvoiced character, formant structure, and dynamic range of instantaneous speech segments. This classification allows a high degree of optimization of the codebooks without increasing either the search time or the data rate. In spite of the short transform approach which has been used, it is shown that flexible methods for bit allocation exist. This application verifies the high robustness of short transform coders to distortions of the transmitted bitstream