| 摘要 |
PROBLEM TO BE SOLVED: To obtain a field discrimination circuit that generates a stable field signal by detecting a total dot clock number for a horizontal period with a horizontal synchronizing signal and a dot clock signal to generate a horizontal pulse signal for field discrimination. SOLUTION: A horizontal address generating section 4 generates a horizontal address signal. A horizontal dot number detection circuit 10 receives this horizontal address signal to hold the address signal with a reference edge of a horizontal synchronizing signal 1 thereby detecting a total dot clock number for one horizontal period. Address data equally dividing the horizontal synchronizing signal are calculated by using the horizontal synchronizing signal 1 and a clock signal from the total dot clock number for the one horizontal period. A horizontal pulse signal required to detect an edge of a vertical synchronizing signal is generated from the data to discriminate a vertical reference edge and to obtain a field signal even when a horizontal frequency division ratio of an input signal is unknown.
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