| 摘要 |
<p>PURPOSE:To make the titled encoder extremely small in quantization error in comparison with that in an encoder having a fixed quantization characteristic by forecasting a sampled value at a present time from a past coded word and encoding by the use of a quantizer having the optimum quantization characteristic. CONSTITUTION:By a decoded value of a previous value stored in a D type flip flop 10, a quantizer and selector 11 selects the quantizer and a reverse quantizer suitable for a sampled value of a present time. The quantizer in which a central quantized value of a part having most concentrated quantizing representative values is present is selected. Then, the sampled value of the present time inputted from an input part 8 is quantized and encoded by the quantizer selected in a quantizer and encoder 9 and outputted to an output part 13. The coding word obtained thereby is decoded by a decoder selected in a decoder and reverse quantizer 12 and reversely quantized and outputted to the D type flip flop 10. Thereby, the quantizing can be constantly performed by an optimum quantizer.</p> |
