| 摘要 |
PURPOSE:To improve the quality of a reproduced voice by finding a sound source signal consisting of multiple pulses in each subframe according to the sound source signal of a past subframe by utilizing pitch correlations between subframes and in a subframe. CONSTITUTION:A subframe division part 355 divides a voice signal into subframes of predetermined time length (including at least plural pitches) equal to or shorter than a frame section. Pitch prediction is carried out among frames by using a sound source signal which is found in a past subframe and stored in a sound source pulse memory 305 to remove the pitch correlation between subframes and then pitch prediction is performed even in the subframe to re move the pitch correlation in the subframe, thereby finding the sound source signal consisting of multiple pulses. Consequently, there is not a large increase in the amount of sent information and the sound quality can be improved with a sent information and the sound quality can be improved with a relatively small arithmetic quantity. |
