| 摘要 |
PURPOSE:To obtain a synthesized voice of high quality by selecting and encoding information in a storage means so that the power of the error signal between a synthesized signal from a synthesizing filter and an input signal becomes minimum. CONSTITUTION:The frame of a driving signal ex is divided into plural equal- length or unequal-length subframes, a equal-interval pulse train which differ in pulse interval, subframe by subframe, is used as the driving signal ex, and the amplitude of the pulse train or information on the amplitude and phase of the pulse train is stored in a code book 900 as vectors previously. The synthesizing filter is driven with the driving signal ex generated based upon vectors in the code book and vectors in the code book 900 are selected and encoded so that the power of the error signal between the obtained synthesized signal and input signal becomes minimum. Consequently, the pulse interval of the driving signal ex is made close in subframes which contains important information or much information or rough in other subframes, so the quality of the composite signal can be improved. |
