Patent ID: 7065338

Claim:
An acoustic parameter coding method, comprising: (a) a step of calculating an acoustic parameter equivalent to a linear predictive coefficient showing a spectrum envelope characteristic of an acoustic signal for every frame of a predetermined length of time; (b) a step of multiplying a code vector outputted in at least one frame in the closest past selected from a vector codebook for storing a plurality of code vectors in correspondence with an index representing said code vectors and a code vector selected in a current frame respectively with a set of weighting coefficients selected from a coefficient codebook for storing one or more sets of weighting coefficients in correspondence with an index representing the weighting coefficients, wherein multiplied results are added to generate a weighted vector and a vector including a component of said weighted vector is found as a candidate of a quantized acoustic parameter with respect to said acoustic parameter of the current frame; and (c) a step of determining the code vector of the vector codebook and the set of the weighting coefficients of the coefficient codebook by using a standard such that a distortion of said candidate of the quantized acoustic parameter with respect to the calculated acoustic parameter becomes a minimum, wherein an index showing the determined code vector and the determined set of the weighting coefficients are determined and outputted as a quantized code of the acoustic parameter.