Fixed codebook searching apparatus and fixed codebook searching method
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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Abstract
A fixed codebook searching apparatus, includes a convolution operator, implemented by at least one processor, that convolves an impulse response of a perceptually weighted synthesis filter with an impulse response vector that has values at negative times, to generate a second impulse response vector that has values at negative times. A matrix generator, implemented by at least one processor, generates a Toeplitz-type convolution matrix using the second impulse response vector generated by the convolution operator. A searcher, implemented by at least one processor, performs a codebook search by maximizing a term using the Toeplitz-type convolution matrix.
16 Citations
14 Claims
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1. A fixed codebook searching apparatus, comprising:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A fixed codebook searching method comprising:
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inputting a speech signal to a speech coding apparatus performing code excited linear prediction (CELP) encoding; convoluting 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, the modifying being implemented by at least one processor, generating a Toeplitz-type convolution matrix calculated from the second impulse response (h(0)(n)); and performing a codebook search by maximizing a term calculated with the Toeplitz-type convolution matrix and an input speech. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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Specification