| 摘要 |
PROBLEM TO BE SOLVED: To prevent quality deterioration when a pitch period and a repetition period are different from each other. SOLUTION: A period preselecting means 23 multiplies a repetition period of an adaptive sound source by a plurality of constants to find repetition period candidates of a plurality of driving sound sources, and selects repetition period candidates of a predetermined number of driving sound sources. A driving sound source encoding means 27 outputs the polarity of a sound source position which minimizes encoding distortion and an evaluated value of the encoding distortion at the time by the repetition period candidates of every predetermined number of driving sound sources. A period encoding means 28 compares evaluated values of encoding distortion by repetition periods, selects repetition period candidates of the driving sound sources based upon the comparison results, and outputs selection information, a sound source position code, and a polarity. COPYRIGHT: (C)2007,JPO&INPIT
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