/vr/ - Retro Games

>>3029159
>What then if a signal that doesn't use 0 as black connects to a VGA display?
Then it's AC coupled with a 220µF capacitor before the 75 ohms termination in the display and doesn't have a fixed black voltage, it will actually vary with the brightness of the signal as the capacitor absorbs the DC/black offset.
A video clamp circuit is used which will restore the black level and such a circuit is used in every 15Khz TV/monitor for this purpose by using the voltage in or around the synctips as reference.
This whole effort actually has it's benefits, as the big capacitors could protect the device video output circuits and it may can filter very low frequencies such as the 50/60hz mains hum which might found it's way into the signal.