Speech encoding apparatus and speech encoding and decoding apparatus

摘要

A speech encoding apparatus capable of averting the deterioration of synthesis speech quality in encoding the input speech and of generating a high-quality synthesis output speech through small quantities of computation. The apparatus includes a target speech generation part for generating from the input speech a target speech vector of a vector length corresponding to a delay parameter; an adaptive codebook for generating from previously generated excitation signals an adaptive vector of the vector length corresponding to the delay parameter; an adaptive code search part for evaluating the distortion of a synthesis vector obtained from the adaptive vector with respect to the target speech vector so as to search for the adaptive vector conducive to the least distortion; and a frame code generation part for generating an excitation signal of a frame length from the adaptive vector conducive to the least distortion.