Presents an efficient method for multipurpose excitation coding using direct vector quantization. This method is then extended to the design of the excitation codebook for a CELP (code excited linear predictive) coder. For the best excitation-vector search at low data rates, an approach combining direct vector quantization and an analysis-by-synthesis procedure is used. Computer simulation results for a 4.8 kb/s speech coder based on the new excitation codebook are presented.
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