| 摘要 |
PROBLEM TO BE SOLVED: To accurately separate a horizontal synchronizing signal from a received composite video signal even when the received composite signal includes any of synchronizing signals such as a binary horizontal synchronizing signal and a ternary horizontal synchronizing signal. SOLUTION: A selector 23 selects either of 2nd and 1st monostable multivibrators 11, 18 on the basis of a detection signal from a ternary synchronizing signal detection circuit 21 and provides an output of a horizontal synchronizing signal of the selected vibrator. Since the 2nd monostable multivibrator 11 selected when the detection signal indicates the selection of the ternary synchronizing signal is configured with a retrigger inhibit type circuit that is triggered at a leading edge of a composite synchronizing signal, the horizontal synchronizing signal generated at the leading edge of the ternary synchronizing signal is obtained. Since the 1st monostable multivibrator 18 selected when the detection signal indicates the selection of the binary synchronizing signal is configured with a retrigger inhibit type circuit that is triggered at a trailing edge of the composite synchronizing signal, the horizontal synchronizing signal generated at the trailing edge of the binary synchronizing signal is obtained.
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