|
RC = Resistor Capacitor there should be such a circuit coupling the vertical to the video to eliminate retrace.
DC restoration has nothing to do with retrace. When video amplifiers are AC coupled (which is the case most sets) the DC level of the video at the detector is normally lost...It manifests it's self in many ways such a scene with one large black and one large white section side by side smearing when fine detail looks good, the brightness immediately after a scene change either being lower or higher than average and sinking or rising despite image content being fairly constant...Things like that.
Some RCAs, Dumonts, etc dedicated a diode in the video output to the task of restoring DC level to the video. I forget the exact electrical description of their operation. They became standard with color TV, but in the monochrome era they usually were only in the more expensive sets.
|