FIXED CODE BOOK SEARCH DEVICE AND FIXED CODE BOOK SEARCH METHOD
First Claim
1. A fixed codebook search method for searching a fixed codebook that generates a fixed codebook vector by convoluting a shape vector with a pulse, the fixed codebook search method comprising the steps of:
- filtering a linear prediction residual signal using a filter having opposite characteristics with respect to a filter that convolutes the shape vector;
limiting pulse position candidates in a pulse vector using a first evaluation function that minimizes error between a signal acquired by filtering using the filter having the opposite characteristic and the pulse vector; and
searching the fixed codebook using the limited pulse position candidates and a second evaluation function.
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Accused Products
Abstract
A fixed code book (FCB) search device simplifies an error minimizing process and reduces a calculation amount so as to prevent deterioration of a coding performance. The FCB search device (100) includes: a pulse shape convolution inverse filter (104) having an inverse feature of a pulse diffusion filter and supplied with an ideal residual signal; a pulse candidate preparatory selection unit (105) for pre-selecting a plurality of pulse candidates from the ideal residual signal to which the inverse filter is applied; and a pulse candidate final selection unit (109) for finally selecting one pulse from the selected candidates. By using this configuration, search is made for an algebra code book to which the pulse diffusion is applied.
32 Citations
7 Claims
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1. A fixed codebook search method for searching a fixed codebook that generates a fixed codebook vector by convoluting a shape vector with a pulse, the fixed codebook search method comprising the steps of:
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filtering a linear prediction residual signal using a filter having opposite characteristics with respect to a filter that convolutes the shape vector; limiting pulse position candidates in a pulse vector using a first evaluation function that minimizes error between a signal acquired by filtering using the filter having the opposite characteristic and the pulse vector; and searching the fixed codebook using the limited pulse position candidates and a second evaluation function. - View Dependent Claims (2, 3)
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4. A fixed codebook search apparatus that searches a fixed codebook that generates a fixed codebook vector by convoluting a pulse with a shape vector, the fixed codebook search apparatus comprising:
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an inverse filter that has opposite characteristics with respect to a filter that convolutes the shape vector and filters a linear prediction residual signal; a first selecting section that minimizes error between a signal and pulse acquired by filtering using the inverse filter and selects a plurality of pulse candidates; and a second selecting section that minimizes error between a target signal and an auditory weighting synthesized signal using a second evaluation function, and selects a pulse from the plurality of pulse candidates. - View Dependent Claims (5, 6, 7)
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Specification