VOICE CODING METHOD, VOICE CODING DEVICE AND VOICE DECODING DEVICE

摘要

PROBLEM TO BE SOLVED: To make the transmitting quantity of a coded word index constant and keep the identifying performance to pitch period in a voice coding/decoding method based on A-b-S(analysis by synthesis) vector quantization using a voice source coded word formed out of only a non-zero amplitude value. SOLUTION: A coefficient unit 2 multiplies a code vector Ci outputted from a composition variable code book 1 after the position of a non-zero sample is controlled on the basis of an index (i) and a transmitting parameter (p) by a gain (g). A linear prediction composing filter 3 inputs the above multiplication result and outputs a regeneration signal gACi. A subtractor 4 subtracts the above regeneration signal gACi from an input signal X, thereby outputting an error signal E. An error power evaluation part 5 calculates the error power on the basis of the error signal E. The above processing is executed to all code vectors Ci and the gains (g), and the index (i) and gain (g) of the code vector Ci where the error power is minimized are calculated and transmitted to a decoder.