| 摘要 |
The spectrum parameter calculator circuit 100 divides a decoded reproduction speech signal into frames and computes a spectrum parameter for each frame. The coefficient calculator circuit 130 shifts a frequency of the spectrum parameter to higher one, and then determines a filter coefficient extended in frequency bandwidth to output it to the composition filter circuit 170. The adder 160 outputs a sound-source signal, which results from addition of a noise signal having a duration equal to the frame length and an adaptive code vector based on a past sound-source signal, to the composition filter circuit 170. The adder 190 uses a sound-source signal extended in frequency bandwidth and adds the signal to a signal resulting from conversion of the reproduction speech signal with a sampling frequency having a higher frequency component to reproduce and output a speech signal extended in frequency bandwidth. <IMAGE> |
