| 摘要 |
PROBLEM TO BE SOLVED: To ensure the maximum utilization of an input dynamic range of an A/D converter, at the time of carrying out the A/D conversion for a video signal by using the A/D converter provided with the differential signal input. SOLUTION: A video signal is clamped and then DC of the signal is adjusted after clamping. Further, it is input into the positive phase of the A/D converter 13 provided with the differential signal input. On the other hand, the middle point potential between an Lo side reference voltage 6 of the above A/D converter and a High side reference voltage 7 is used for the input of an inverse amplifier 14 so as to make the negative phase input signal of the A/D converter. It is made possible to carry out the maximum utilization of the input dynamic range of the A/D converter, by applying a negative feedback to a DC shift circuit 4 after D/A converting, in comparison with the digital reference requiring to clamp the signal after the A/D conversion. COPYRIGHT: (C)2006,JPO&NCIPI
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