Those old circuits were designed for old fairly blurry video, not for modern very clear high definition video.
Video amplifiers are never paralleled. Why do you need to parallel them? Each video amp drives its own 75 ohm cable and feeds one 75 ohm video monitor.
23 years ago I made video amplifiers like the Elektor circuits that were printed 23 years ago. Make them now if you want.
The levels for the video fader must be accurate so that the sync pulses are not attenuated. How will you synchronize the video signals when fading?
If the two video signals do not have their sync's synchronized then fading from one to the other will result in a loss of sync and the picture will be a mess.
Instead of fading you can abruptly switch from one video and its sync to the other.
You can do a 'dirty' cross fade by fading one source to black, switching to the second source, including it's syncs, while it is also black then bringing the second level up. It doesn't synchronize the video sources and although both will be faded right down during the switch, the monitor/recorder might still sees a discontinuity in the sync patterns and cause a visible picture tear or roll.
Brian.
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?