Vector quantization coder and decoder modifications.

摘要

PURPOSE:To save a memory capacity of a code book required for coding and decoding processing by adopting the constitution of plural code books and providing a synthesis means. CONSTITUTION:Code books 10-i of plural sets manage plural signal vectors while giving an index. Moreover, prediction filters 30-i prepared in pairs with the code books 10-i reproduce a signal vector of the code books 10-i in pairs to reproduce a signal waveforms and a synthesis means 40 calculates the total sum of signal waveform reproduced by each of the prediction filters 30-i. Furthermore, an error calculation means 50 calculates an error between a reproduction signal waveform calculated by the synthesis means 40 and a signal waveform being an object of coding, an error evaluation means 60 specifies a least power among the power values of the error calculated by the error calculation means 50, a control means 70 selects sequentially the combination of signal vectors in the code books 10-i and gives the signal vector to each prediction filter 30-i. Thus, the signal is reproduced with high quality without increasing the quantity of calculation and of the hardware.