| 摘要 |
PROBLEM TO BE SOLVED: To permit the smooth expansion and compression of waveform signals and to permit processing in real time by forming at least, either of frequency information and amplitude information to the waveform signals corresponding to the respective infrequency bands divided to plural infrequency band groups. SOLUTION: A multirate analysis section comprises a multirate preprocessing section for dividing the waveform signals to main bands and sub-bands, a sub- band analysis section for analyzing the amplitude values and instantaneous frequencies of the respective sub-bands and a memory section for storing the amplitude values and instantaneous frequencies analyzed by the sub-band analysis sections. The processing in the respective sub-band analysis sections is divided to the four sub-bands, by which the amplitude values and instantaneous frequencies are analyzed. The data amplitude value and instantaneous frequency of the respective analyzed sub-bands is limited in the bands and, therefore, the sampling frequencies are considerably thinned and the information quantity may be compressed and may be stored into the memory section. As a result, the reproduced sounds do not have flat sounds even of the waveform signals are expanded and compressed. |
