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Method and apparatus for hybrid coding of speech at 4kbps

  • US 6,233,550 B1
  • Filed: 08/28/1998
  • Issued: 05/15/2001
  • Est. Priority Date: 08/29/1997
  • Status: Expired due to Term
First Claim
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1. A hybrid speech encoding method, comprising the steps of:

  • (a) classifying frames of speech signals as voiced, unvoiced, or transitory;

    (b) using harmonic coding to compress frames associated with at least one of said classes;

    (c) coding frames classified as transitory using a coding technique selected from the group consisting of waveform coding, analysis-by-synthesis coding, codebook excited linear prediction analysis-by-synthesis coding, and multipulse analysis-by-synthesis coding; and

    (d) phase aligning a harmonic coded frame in a decoder when the preceding frame has been waveform encoded for pairs of adjacent frames comprising a waveform encoded frame adjacent to a harmonic coded frame.

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