| 摘要 |
PROBLEM TO BE SOLVED: To detect a vertical synchronizing signal with high reliability without depending greatly on external analog processing performance. SOLUTION: This vertical synchronizing signal detection circuit is provided with an edge detection circuit 400, that detects an edge of a composite synchronizing signal that is received and separated from a composite video signal and generates a pulse synchronously with the detected edge as an edge signal, a pulse width expansion circuit 500 that generates a pulse signal with a prescribed pulse width resulting from expanding the edge signal obtained from the edge detection circuit 400, a signal synthesis circuit 600 that synthesizes a pulse signal obtained from the pulse width expansion circuit 500 with an input composite synchronizing signal, and a vertical synchronization detection section 100 that integrates the synthesis signal obtained from the signal synthesis circuit 600 to detect a vertical synchronizing signal when the integral value exceeds a prescribed threshold value.
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