| 摘要 |
PROBLEM TO BE SOLVED: To decrease the selective calculating amount of a noise exciting signal. SOLUTION: Matrices H and H<t> H=R using the impulse response of a synthesizing filter as elements are determined by a calculation part 31 after selecting a pitch exciting signal (p), andψis determined by another calculation part 32 from H, R, signal (p) and input voice (s), and preliminary selection part 33-37 calculate ajψ(lj ) for vector elementsψ(i) ofψabout eight pulse positions lj and their polarities aj in groups 0-4, and in the sequence from greater value of ajψ(lj ), for example, three pulse positions are preliminarily selected, and a candidate preparing part 38 prepares a noise exciting signal (c) of five pulses as one selection each from the three positions among group 0-4, and for each (c),ψc is calculated and also distortion for (s) is calculated so that the optimum noise exciting signal is selected.
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