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Speech decoding method and apparatus for selecting random noise codevectors as excitation signals for an unvoiced speech frame

  • US 5,909,663 A
  • Filed: 09/05/1997
  • Issued: 06/01/1999
  • Est. Priority Date: 09/18/1996
  • Status: Expired due to Term
First Claim
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1. A speech decoding method for decoding an encoded speech signal produced by dividing an input speech signal on a time axis using a pre-set encoding unit and by waveform-encoding a resulting encoding-unit-based time-axis waveform signal, said method comprising:

  • a waveform-decoding step for producing an encoding-unit-based time-axis waveform signal, wherein said time-axis waveform signal is an excitation signal for synthesis of an unvoiced speech signal;

    an error detecting step for detecting an error using an error checking code appended to said encoded speech signal; and

    an evading step for evading repeated use of a same waveform as a waveform used in said waveform-decoding step by using a waveform different from a directly preceding waveform when an error is detected in said error detecting step.

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