| 摘要 |
PROBLEM TO BE SOLVED: To prevent such quality deterioration that wave form property is not stored and the articulation of reproduced speech becomes bad in a speech coding/decoding device using time compression expansion. SOLUTION: A speech decoding means has a speech coding means having a auto- correlation coefficient calculating part 11 for calculating the auto-correlation coefficient of an input speech signal, a maximum value detecting part 12 for detecting the maximum value of the auto-correlation coefficient, a judging part 13 for judging the relative values between the maximum value of the auto-correlation coefficient and a threshold value, a pitch period extracting part 16 for making the delayed amount (k) in which the auto-correlation coefficient is maximum as the pitch period of a speech signal, and a time compression part 17 for performing time base compression processing of the speech signal, and a time expansion part 21 for performing time expansion processing. When the maximum value is larger than the threshold value, time compression processing is performed with the speech coding means and the speech composing means, and when it is smaller than the threshold value, time base expansion processing is performed with the speech coding means and the speech decoding means. |
