| 摘要 |
<p>PURPOSE:To suppress the increase of quantizing noises, by selecting plural quantizing characteristics by detecting not only the occupied ratio of a buffer memory but also the increasing ratio of the memory and fine quantizing characteristics when those ratios are lower than prescribed values. CONSTITUTION:Inputted TV signals are temporarily stored in a buffer memory 4 after they are converted into PCM signals by an A/D converter 1 and encoded in terms of difference at a difference encoder 2, and then, encoded in terms of variable length by a variable length encoder 3. The content of the memory 4 is read out at a speed corresponding to the transmitting bit rate and sent out to a transmission line. On the other hand, it is arranged that the difference encoder 2 can be switched in terms of the quantizing characteristic depending on the occupied ratio and increased ratio of the buffer memory 4, and therfore, a control signal for selecting quantizing characteristics is impressed upon the difference encoder 2 from the memory 4. Therefore, the information generating quantity of the output of the encoder is controlled.</p> |
