| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to perform an optimum scaling and to make it possible to optimally set gain fluctuation caused by a post filter by beforehand obtaining a gain fluctuation value caused by the post filter. SOLUTION: A voice signal is synthesized from an excitation signal by a synthetic filter 22, and the voice quality is improved by the post filter 24. The post filter 33 with a characteristics similar to the post filter 24 is awaited, and the gain of the post filler 24 is estimated before hand from the input/output of the post filter 33. An optimum scaling value when filter operation in the post filter 24 is performed is set using the gain obtained from the input/output of the post filter 3, and the optimum gain when the gain fluctuation caused by the post filter is controlled is set by a gain control circuit 27. |
