| 摘要 |
PURPOSE: To adjust a video signal smoothly and to allow the circuit to be applied to flexible adjustment purpose. CONSTITUTION: A composite video signal CV, a luminance signal Y, color signals R, G, B or the like are fed to a gate 18 of an insert section 17 as an input video signal Vin. Reference level signals REFa, REFb from a generator 19 are fed to gates 20, 21 of the insert section 17. The signal REFa has a 100% level. The signal REFb has an optional level and the level is revised by key operation. Insert timing signals ITa, ITb from a generating section 22 are fed respectively to the gates 18, 20, 21. An output video signal Vout let to an output terminal 4 are respectively replaced with the reference level signals RFFa, REFb only for a horizontal period when the timing signals ITa, ITb are logical H in the input video signal Vin. The video signal Vout, is fed to a waveform monitor, on which a state of the signal superimposition between a waveform of the the signal Vin and the reference levels is observed. |
