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Multistage positive product vector quantization for line spectral frequencies in low rate speech coding

  • US 6,141,640 A
  • Filed: 02/20/1998
  • Issued: 10/31/2000
  • Est. Priority Date: 02/20/1998
  • Status: Expired due to Fees
First Claim
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1. A low bit rate method of communicating an input vector X representing an audible signal through a channel comprising the steps of:

  • a) quantizing the input vector X to determine a scalar scaling factor f and a codevector C;

    b) looking up codevector C and scaling factor f in a codebook to create an index Ic ;

    c) subtracting the codevector C from the original input vector X to result in an error vector E;

    d) scaling the error vector E by scaling factor f to result in scaled error vector J;

    e) selecting a plurality of base vectors Jp having all positive components to comprise a base codebook;

    f) creating a unit sign vector s having the same dimensions as vector J with same signs for each component as J;

    g) switching the polarity of all negative components of input vector J to create Jp ;

    h) finding an index, Ip, of the vector in the base codebook closest to Jp ;

    i) transmitting the index Ip, sign vector s, and index Ic to a receiver/decoder.

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