Patent ID: 6393394
Filing Date: 2002-05-21
Classification: G10L

Abstract:
A speech coder, comprising:a linear predictive filter configured to analyze a frame and generate a line spectral information codevector based thereon; and a quantizer coupled to the linear predictive filter and configured to vector quantize the line spectral information vector with a first vector quantization technique that uses a non-moving-average prediction-based vector quantization scheme, wherein the quantizer is further configured to compute equivalent moving average codevectors for the first technique; update a moving average codebook of codevectors for a predefined number of frames that were previously processed by the speech coder with the equivalent moving average codevectors; compute a target quantization vector for the second technique based on the updated moving average codebook memory; vector quantize the target quantization vector with a second vector quantization technique to generate a quantized target codevector; the second vector quantization technique using a moving-average prediction-based scheme; update the memory of the moving average codebook with the quantized target codevector; and compute quantized line spectral information vectors from the quantized target codevector.