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Half-rate vocoder

  • US 8,595,002 B2
  • Filed: 01/18/2013
  • Issued: 11/26/2013
  • Est. Priority Date: 04/01/2003
  • Status: Expired due to Term
First Claim
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1. A speech coder configured to encode a sequence of digital speech samples into a bit stream, the speech coder being operable to:

  • divide the digital speech samples into one or more frames;

    compute model parameters for a frame;

    quantize the model parameters to produce pitch bits conveying pitch information, voicing bits conveying voicing information, and gain bits conveying signal level information, wherein the pitch bits, the voicing bits and the gain bits are included in quantizer bits for the frame;

    combine one or more of the pitch bits with one or more of the voicing bits and one or more of the gain bits to create a first parameter codeword that includes less than all of the quantizer bits for the frame;

    encode the first parameter codeword with an error control code to produce a first FEC (“

    forward error control”

    ) codeword; and

    include the first FEC codeword in a bit stream for the frame.

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