| 摘要 |
PURPOSE:To reduce the malfunction caused by the impulsive noise piled onto the horizontal synchronous signal, by adding the circuit which detects the horizontal scanning period through counting of the division horizontal synchronous signal which is obtained by dividing the oscillation frequency. CONSTITUTION:The signal is supplied to terminal 11, and counter circuit 12 starts counting the signals of terminal 11 with the input of the detection pulse obtained through vertical synchronous signal detector circuit 13. Then the signal which is delivered when counter 12 reaches the prescribed count value is supplied to signal process circuit 14, and thus the pulse gating No.19H is delivered to terminal 16. At the same time the gate pulse of the horizontal scanning period and to be killed via signal process circuit 15 is delivered. Thus the signal obtained by dividing the signal used for the color signal process is counted not the horizontal synchronous signal obtained by isolating the signal of terminal 11 from the video signal. In such way, not only No.19H gate pulse but the gate pulses before and after the No.19H gate pulse can be produced. |
