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Speech coder

  • US 5,208,862 A
  • Filed: 02/20/1991
  • Issued: 05/04/1993
  • Est. Priority Date: 02/22/1990
  • Status: Expired due to Term
First Claim
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1. A speech coder comprising:

  • means for dividing a discrete input speech signal into signal components in units of frames each frame having a predetermined time length, and for generating a spectrum parameter representing a spectrum envelope of said discrete input speech signal;

    means for generating a subframe signal by dividing the frame into subframes each subframe having a predetermined time length, and for calculating a pitch parameter using a correlation between said discrete input speech signal and synthetic speech calculated from an excitation signal generated from a previous discrete input speech signal;

    a first code book for storing code vectors formed by off-line training based on a speech signal data base;

    a second code book for storing code vectors having predetermined statistical characteristics; and

    means for generating an excitation signal of the discrete input speech signal by a linear combination of a code vector selected from said first code book in accordance with each obtained subframe signal and a code vector selected from said second code book, and outputting an index of said code vector selected from said first code book and an index of said code vector selected from said second code book together with said spectrum parameter and said pitch parameter.

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