| 摘要 |
<p>PURPOSE:To enable to deliver with the minimized deterioration of picture quality, by opening coding loop between frames and decoding loop through the detection of frame synchronism skip, and by closing the loops in the timing of the synchronism of between frames after the elapse of protection time. CONSTITUTION:When the frame synchronism slip of picture signal is caused, it is detected with the frame synchronism detection circuit 1. Then, the switch circuit 6 is selected to the terminal b, opening the loop and a given voltage A is added to the terminal b. On the other hand, at the reception side, the frame timing pick up and reception circuit 11 detects the distortion of the frame timing signal. Then, the switch circuit 16 is selected to the terminal d, opening the loop and a given voltage B is fed to the terminal d, and decoding output is obtained from the in-frame decoder 14. Further, after protection time, the coding loop is closed in the timing of frame synchronism of video signal, control signal is fed to the reception side, and at the reception side, the terminal of the circuit 16 is returned to c and the decoding loop between frames is closed. Thus, the delivery with minimized deterioration of picture quality can be obtained.</p> |
