| 摘要 |
PURPOSE:To convert a video signal transmitted as a still picture with a low- speed AD converter by moving sequentially a sampling point at each frame of an analog video signal to repeat AD conversion. CONSTITUTION:The AD converter 2 uses a sampling clock signal (b) supplied from a delay circuit 1 to sample an analog video signal and converts the signal into a digital signal. The converted signal is stored in a RAM 8 via a latch circuit 3. After all sampling are finished at the 1st frame, the sampling of the next frame is executed. The start point of sampling is slightly moved at each transmission of one frame by the control of an address counter 7. The operation above is executed for all frames, e.g., 64 frames. Thus, a still picture signal is subjected to high-speed AD conversion by using a low-speed AD converter.
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