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Audio encoding and decoding system realizing vector quantization using code book in communication system

  • US 5,970,443 A
  • Filed: 09/22/1997
  • Issued: 10/19/1999
  • Est. Priority Date: 09/24/1996
  • Status: Expired due to Fees
First Claim
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1. An audio encoding-decoding system comprising:

  • an audio encoder which uses a code book to perform vector quantization on residual signals, corresponding to residuals of an analysis of linear predictive coding which is performed on audio signals by certain intervals of time, so as to produce vector quantization indexes, wherein the audio encoder provides a coded output which contains the vector quantization indexes and information representing a result of the analysis of the linear predictive coding;

    information quantity control means for performing elimination of indexes which correspond to a part of the vector quantization indexes contained in the coded output of the audio encoder in response to an information quantity control request so as to control an information quantity of the coded output, said information quantity control means also adding information representing a control level of the information quantity to the coded output, wherein the indexes of the elimination correspond to the part of the vector quantization indexes which has low influence on reproduction of audio information; and

    an audio decoder for decoding the coded output, whose information quantity is controlled by the information quantity control means, on the basis of the information representing the control level of the information quantity, thus reproducing the audio signals.

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