| 摘要 |
PURPOSE:To simplify the constitution of a device, by providing a position for clamping a video signal in addition to a horizontal synchronizing signal period including a equivalent pulse period and a pedestal period to perform correctly the clamp of a signal when an interfering signal such as a ghost is mixed. CONSTITUTION:A synchronizing pulse from a input terminal 1 is differentiated and shaped by a differential shaping circuit 6 and made to a reset pulse for the next stage of a counter circuit 7. A pulse C, which is of 8 times a horizontal frequency (fH), is inputted to the circuit 7 from a terminal 8, and a pulse D is outputted with a specified delay behind the synchronizing pulse by FFs 10 and 11 and an ANd circuit 12. The pulse D is supplied to the AND circuit 12 where signals E and F from terminals 13 and 14 are inputted, and the circuit 12 outputs a pulse D'. The pulse D' is supplied to a clamp circuit 20 as a clamp input to set up a clamping position in addition to a horizontal synchronizing signal perido including a equivalent pulse period and a pedestal period, and thus signals which contain interfering signals such as a ghost are correctly clamped. |
