Improving performance of code excited LPC-coders by joint optimization

Abstract This article describes a CELP speech coding algorithm where the coder parameters are jointly optimized. For that, the relation between pitch period, pitch predictor coefficient, codebook entry and scaling factor is derived. Different approaches to solve this optimization problem with low computational load are discussed. It is shown that the length of the excitation codebook can be reduced significantly compared to the sequential optimization of the coder parameters. The influence of the parameter quantization is examined and an estimation of the computational load is given.

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