| 摘要 |
PURPOSE:To make adjustment of the beam quantity possible without a waveform monitor and so on, by switching the gain of a video amplifier and by giving the reference level to a video signal and by superposing a beam set pulse equal to a negative-polarity video rated output to a video signal. CONSTITUTION:In gain switching circuit 12, the circuit to attenuate the input signal to 1/n and the bypass circuit are selected by the change-over switch. Reference level gate circuit 13 gates the left video period of the screen center in the reference level. Reference level gate pulse 3 and beam set pulse 4 are generated by pulse generating circuit 16. In mixing circuit 4, negative-polarity beam set pulse 4 equal to the video rated level and the video signal are superposed. Then, video signal 2 is supplied to view finder display circuit 15. |
