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Method and system for encoding digital speech information

  • US 4,718,087 A
  • Filed: 05/11/1984
  • Issued: 01/05/1988
  • Est. Priority Date: 05/11/1984
  • Status: Expired due to Term
First Claim
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1. A method of encoding digital speech information to characterize spoken human speech with an optimally reduced speech data rate while retaining speech quality in the audible reproduction of the encoded digital speech information, said method comprising:

  • storing digital speech information as digital speech data in the form of quantized speech parameter values comprising a plurality of speech data frames;

    determining the transition probabilities for corresponding quantized speech parameter values in the next successive speech data frame in relation to the current speech data frame;

    establishing the conditional probabilities as to the quantization values of the speech parameters of successive speech data frames based upon the determination of the transition probabilities; and

    representing the respective quantization values of the speech parameters after the conditional probabilities have been established by a digital code wherein digital codewords of variable length represent quantization values in accordance with their probability of occurrence such that more probable quantization values are assigned digital codewords of a shorter bit length while less probable quantization values are assigned digital codewords of a longer bit length.

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