| 摘要 |
PURPOSE:To improve the quality of a synthesized voice by making code vectors of a noise code book periodic. CONSTITUTION:In code driving linear predictive encoding, one cycle is set among plural predetermined kind of cycles, an excitation vector is obtained from an adaptive code book with the cycle, and the code vectors in the noise code book are made periodic respectively with the cycle; and respective synthesizing filters are excited with the respective sums of the cyclic code vectors and excitation vector to regenerate a voice, the code vector (index) of the noise code book which minimizes the distortion of the regenerated voice to the input voice is determined temporarily, and similar processing is repeated for all determined kind of cycles, thereby selecting the noise index of minimum distortion and its period from the temporarily determined index. |
