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Multi-pulse speech coder

  • US 4,944,013 A
  • Filed: 04/01/1986
  • Issued: 07/24/1990
  • Est. Priority Date: 04/03/1985
  • Status: Expired due to Term
First Claim
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1. A method of speech coding comprising:

  • receiving speech samples;

    processing the speech samples to derive parameters representing a response of a synthesis filter;

    deriving, from the parameters and the speech samples, pulse position and amplitude information defining an excitation consisting, within each of successive time frames corresponding to a plurality n of said speech samples, of a pulse sequence containing a smaller plurality k of pulses;

    wherein the pulse position and amplitude information of the k pulses is derived by;

    (1) deriving an initial estimate of the positions and amplitudes of the k pulses, and(2) carrying out an iterative adjustment process by;

    (a) selecting individual ones of the k pulses according to predetermined criteria, and(b) substituting for each such selected pulse a pulse in an alternative position whenever a computed error signal is thereby reduced, said error signal being obtained by comparing speech samples with the response of a filter having said parameters to an excitation which includes said selected pulse and others of said pulses, said substituted alternative position thereby being obtained as a function of the position and amplitudes of said other pulses.

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