| 摘要 |
<p>PURPOSE:To simplify the hardware without deteriorating the efficiency of encoding, by performing the estimate-encoding for the high order bits only and quantizing the low order bits adaptively, in place of the estimates encoding of all the bits. CONSTITUTION:An analog signal (picture signal) encoded in 8-bit is applied to a distributor 5 of an encoder 31, where the high order 6-bit is applied to an estimate-encoder 33 and the low order 2-bit is to an quantizer 7. The encoder 33 changes over the characteristics (encoding/quantization) in response to a control mode signal from a control circuit 35 for the estimate encoding and outputs an estimated error signal to a code converter 34. The quantizer 7 quantizes signals according to the quantizing characteristic selected with the mode signal and outputs a quantized output signal to a code converter 34. The converter 34 converts the supplied signal according to the mode signal and multiplexes the signal with the mode signal. The control circuit 35 monitors the content of a smoothing buffer memory in matching with the transmission speed of a transmission line and outputs the mode signal so as not to produce overflow/underflow.</p> |
