| 摘要 |
<p>PURPOSE:To obtain a data tracing both a steep change and a slow change by classifying a predicted value at a prescribed reference level and quantizing the difference value according to a quantization reference set separately in response to the prediction level. CONSTITUTION:A predicted level is classified into 8 stages to set 8 kinds of quantization references and a conversion table from a difference into a quantization characteristic is stored in a code quantization circuit 32 in response to each predicted level. Moreover, the conversion table from the quantization characteristic into a 4-bit code is stored in a code conversion circuit. A subtraction circuit 31 of a coding section 3 generates a difference value with a predicted value outputted from a prediction circuit 35. A code quantization circuit 32 obtains a quantization characteristic value by using a conversion table in response to an output of a predicted level discrimination circuit 36 from the difference value. Moreover, the code conversion circuit 33 converts the quantization characteristic into a 4-bit code by using the conversion table in response to the output of the circuit 36.</p> |
