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Fixed codebook searching apparatus and fixed codebook searching method

  • US 8,452,590 B2
  • Filed: 04/25/2011
  • Issued: 05/28/2013
  • Est. Priority Date: 03/10/2006
  • Status: Active Grant
First Claim
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1. A fixed codebook searching apparatus, comprising:

  • an impulse response modifier, implemented by at least one processor, that convolutes a first impulse response (h(n)) with an impulse response of a non-causal filter to generate a second impulse response (h(0)(n)), in a code excited linear prediction (CELP) encoder, the second impulse (h(0)(n)) having a value where an index (n) in time domain equals a negative integer;

    a matrix generator that generates a Toeplitz-type convolution matrix from the second impulse response (h(0)(n)); and

    a searcher, that performs a codebook search by maximizing a term using the Toeplitz-type convolution matrix and an input speech signal,wherein the fixed codebook searching apparatus, comprising the impulse response modifier, the matrix generator and the searcher perform a code excited linear prediction (CELP) encoding of the input speech signal.

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