| 摘要 |
PROBLEM TO BE SOLVED: To surely detect video identification signals from video signals by measuring horizontal synchronizing signals with vertical synchronizing signals as reference, judging whether or not the video signals read corresponding to a measured value are the video identification signals based on prescribed signal components in the video signals and updating the counted value of a counting means in the case of judging that they are not. SOLUTION: A signal read circuit 3 reads the video identification signals and outputs them to a CRCC arithmetic circuit 5 when a line number from a line counter 2 is 20H and 283H. They are judged as the video identification signals when the arithmetic result of the CRCC arithmetic circuit 5 matches with CRCC and is correct and the judged result is outputted to a line counter control circuit 4 when it is not. The line counter control circuit 4 forcibly updates the counted value of the line counter 2 for a prescribed value so as to search the line number where the video identification signals are present. By the forcible updating of the counted value, the signals of lines other than 20H and 283H are read as well.
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