| 摘要 |
PROBLEM TO BE SOLVED: To improve the characteristic of a post filter used for the spectrum shaping of the decoded signal of a voice decoding device and the improvement in auditory quality, and perform a more effective post filter processing. SOLUTION: The filter coefficient of a spectrum shaping filter 440 within a post filter to which a coded voice signal is decoded and supplied is renewed in a frame period, and the gain of a gain adjusting circuit 443 for correcting the gain change by the spectrum shaping is renewed in a sub-frame period which is 1/8 of the frame period. The switching of the filter coefficient can be performed in such a manner that the following speed is quickly and smoothly changed, and the level fluctuation by frequent gain switching can be suppressed. |
