| 摘要 |
<p>PURPOSE:To cause a quantizing noise to be small by time-dividing a video signal to be analog-digital-converted into a synchronizing signal part and a video information part and causing the synchronizing signal to be within the amplitude of the image information. CONSTITUTION:A video signal time division multiple circuit 36 inserted before the input of an A/D converter 14 and a video restoring circuit 37 after the output of a D/A converter 16 are provided. By the video signal time division multiple circuit 36, the video signal is divided into a period to include the synchronizing signal and the period except for it, individual clamping reference voltages are set, respectively, and thereby, the synchronizing signal is made to be within the amplitude range of the signal to express the video information. Simultaneously, by the video signal restoring circuit 37, the time-division- multiplexed video signal is restored to the form of the original video signal. Thus, at the time of an A/D conversion, a quantizing gradation number obtained to the video information part can be made large, and the quantizing noise can be made small by the degree.</p> |
