| 摘要 |
PURPOSE:To decrease the retrieval time by controlling variably the number of stages of vector quantization of tree retrieval vector adopted for a vector quantization section after normalization with an amplitude in a block by means of the amplitude in block so as to improve the quantization efficiency. CONSTITUTION:K-set of input signal series are formed into blocks, a mean value separation normalizing circuit 14 calculates an interblock mean value 15 to an input signal vector 1, the mean value is separated, an interblock amplitude 16 is calculated and a mean value separation normalizing vector 18 is obtained. The vector 18 is taken as an input vector for vector quantization, and when it is fed to a TSVQ coder, a tree retrieval vector quantization is applied by the 1st stage 19 - the 3rd stage 23 of the TSVQ coder. The coder controls variably the number of stages of the tree retrieval vector quantization by a coding control section 17 so as to attain variable length coding. |
