VOICE ENCODER, VOICE DECODER, RECORDING MEDIUM ON WHICH PROGRAM FOR REALIZING VOICE ENCODING/DECODING IS RECORDED AND MOBILE COMMUNICATION APPARATUS

摘要

The voice quality of a voice source generating unit in a CELP-type voice encoder and a CELP-type voice decoder is improved. The pitch peak position of an adapted code vector is obtained by a pitch peak position calculator (12), a window by which the amplitude of the pitch peak position is intensified is generated by an amplitude intensifying window generator (13) and the amplitude of a noise code vector corresponding to the pitch peak position is intensified by an amplitude intensifying window applyer (16). Alternatively, the searching position of a pulse is so determined as to be thick near the pitch peak position and thin in the other parts and the pulse position is found in accordance with the determined searching positions. Alternatively, by utilizing the pitch peak position and pitch period information in a subframe immediately before and the pitch period information in a subframe at present, the voice source construction is changed backward adaptably to improve the voice quality and suppress the propagation of the influence of a transmission line error.