| 摘要 |
The vertical sync signal generator includes: a vertical sync signal separation circuit for separating a vertical sync signal of an input luminance signal and outputting the separated signal as a first vertical sync signal; an automatic frequency control circuit for generating a second vertical sync signal having a repeat frequency corresponding with an average repeat frequency of the first vertical sync signal and outputting the generated signal; a vertical sync signal phase detection circuit for detecting whether or not the first vertical sync signal has two different periods repeated alternately and outputting the detection result as a decision signal; and a selector for receiving the first and second vertical sync signals, selecting the first vertical sync signal when the decision signal indicates that the first vertical sync signal has two different periods repeated alternately and otherwise selecting the second vertical sync signal and outputting the selected signal.
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