| 摘要 |
PURPOSE:To display a video signal waveform on a TV receiver with a simple constitution by using an A/D converter, a digital comparator, a timing signal generator, a counter, an adder, etc. CONSTITUTION:A video signal from a VTR is supplied to a digital comparator 25 through the A/D converter 11 and also supplied to the adder 26, and the signal is further supplied to a timing circuit 23 equipped with a horizontal synchronizing signal separating circuit 21 and a vertical synchronizing signal separating circuit 22. Then a horizontal synchronizing signal outputted by the circuit 23 is used as a clock and a counter 24 where the number of scanning lines is set counts down at every scanning line. Its counted value is applied as a reference value to the digital comparator 25, which outputs a 1 signal to the adder 26 when the reference value coincides with the output of the converter 11, so that the video signal waveform is displayed on a TV receiver 27. Thus, the video signal waveform is displayed on the TV receiver by the simple constitution which requires neither a microcomputer nor an oscilloscope, etc.
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