| 摘要 |
PURPOSE:To improve the tone quality by obtaining a pattern of a smooth delay of an adaptive code book, and also, suppressing a noise sense which is a problem point of a voice encoding system of a CELP system, in the voice encoding system of about 8-4kb/s. CONSTITUTION:Valcalization is discriminated at every frame, and in the frame which is discriminated to be valcalization, at the time of searching an adaptive code book, to a sound source for delaying a sound source in the past, a COM filter corresponding to its delay is set, and a delay by which a square error of an output of the COM filter and a weighting signal becomes minimum is derived. In the case it is not discriminated to be valcalization, the COM filter is not used. At the time of being voicedness, with respect to an output of the adaptive code book, two ways of constitutions in the case the COM filter is used, and in the case the filter is not used can be taken. |
