PROBLEM TO BE SOLVED: To realize reproduced voice quality that is easier to here by performing an optimum velocity ratio control according to fluctuation of a voice content rate.;SOLUTION: A voice period and a non-voice period are determined in a voice/no-voice determination section 11 and a voice content rate in a frame length for calculation is calculated as voice information in a voice information calculation section 12, and an average value and a standard deviation of the voice content ratio are calculated. Then, the velocity ratio in the voice period is calculated for each frame using the voice information in a velocity ratio calculation section 14, and the velocity ratio in the non-voice period is calculated so that regeneration time may become a target regeneration time using the velocity ratio in the voice period. Based on the calculated velocity ratio in the voice period and the non-voice period, a regeneration velocity of an input voice signal is changed in a voice velocity changing section 15 and the voice signal is output.;COPYRIGHT: (C)2007,JPO&INPIT
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