| 摘要 |
PURPOSE:To reproduce a voice excellently with a small arithmetic quantity irrelevantly to a bit rate by dividing a frame into subframes corresponding to a pitch period and using multipulses which are found by pitch interpolation and multipulses which are found on the whole frame without pitch prediction. CONSTITUTION:The voice signal from an input terminal 100 is divided into specific frames and an LPC and a pitch analysis part 150 finds an LPC coefficient of specific degree as a spectrum parameter representing a spectrum envelope from the voice signal of a frame. A pitch interpolation multipulse calculator 250 divides the frame into subframes by using a pitch period, finds the amplitude and position of multipulses in one specific section, and finds gain correction coefficients and phase correction coefficients of other subframes. Then a sound source signal is restored by specific arithmetic operation through a subtracter 260 and a multipulse calculation part 270 and then processed by composition. Consequently, the excellent voice can be reproduced with a small arithmetic quantity irrelevantly to the bit rate. |
