| 摘要 |
PURPOSE:To lower the speed of video signal faithfully by controlling two analog switches by the gate signals from two comparators thereby sampling the video signal. CONSTITUTION:The output (b) of the sawtooth wave generator 2 of a flaw detector 9 and the video signal from a reception part 6 are inputted respectively to comparators 11, 19 and an analog switch 15. The signal (i) from a sawtooth wave generator 21 which outputs the sawtooth waves (i), (j) [i<j] of two kinds of different levels is applied to the comparator 19, by the output whereof the switch 15 and a peak holding circuit 16 are controlled. The sawtooth wave signal (i) is applied to the comparator 11, by the output thereof an analog switch 22 is controlled. Thence, the voltage of a capacitor C holding the output of the switch 15 is held in a holding circuit 16. Since the video signal (e) is sampled in this way, the video signal is faithfully made lower is speed without using the sampling pulses of narrow pulse width. |
