| US 7,519,533 B2 | ||
| Fixed codebook searching apparatus and fixed codebook searching method | ||
| Hiroyuki Ehara, Kanagawa (Japan); and Koji Yoshida, Kanagawa (Japan) | ||
| Assigned to Panasonic Corporation, Osaka (Japan) | ||
| Filed on Mar. 08, 2007, as Appl. No. 11/683,830. | ||
| Claims priority of application No. 2006-065399 (JP), filed on Mar. 10, 2006; and application No. 2007-027408 (JP), filed on Feb. 06, 2007. | ||
| Prior Publication US 2007/0213977 A1, Sep. 13, 2007 | ||
| Int. Cl. G10L 19/12 (2006.01) | ||
| U.S. Cl. 704—223 [704/221; 704/222; 704/246] | 8 Claims |
| 1. A fixed codebook searching apparatus that is included in a speech coding apparatus performing a code-excited linear prediction
(CELP) encoding of an input speech signal using a pulse excitation vector searched in the fixed codebook searching apparatus
and outputting an encoded bit sequence including a parameter corresponding to the pulse excitation vector, the fixed codebook
searching apparatus, comprising:
a pulse excitation vector generating section that generates a pulse excitation vector specified by a searching section;
a first convolution operation section that convolutes an impulse response of a perceptually weighted synthesis filter with
an impulse response vector which has one or more values at negative times, to generate a second impulse response vector that
has one or more values at negative times;
a matrix generating section that generates a Toeplitz-type convolution matrix by the second impulse response vector generated
by the first convolution operation section; and
the searching section that inputs a target signal obtained from the input speech signal in the speech coding apparatus, performs
convolution processing on the pulse excitation vector generated by the pulse excitation vector generating section using the
matrix generated by the matrix generating section, and controls the pulse excitation vector generated by the pulse excitation
vector generating section for minimizing an error between a perceptually weighted synthesis signal obtained by the convolution
processing and the target vector, and outputs a parameter corresponding to the pulse excitation vector that minimizes the
error.
|