Using an arbitrary waveform generator to output composite video signal

[JustAnotherGuy999]

for example: can we play around with an arbitrary waveform generator to create a waveform that outputs a "point" with a certain color in a certain position to a tv (through a yellow RCA connector).

[Richard Crowley]

It seems unlikely with most common AWG.
A composite analog TV signal is at least 3 different arbitrary waveforms:
1) The actual lines of video signal that are visible on the screen.
2) The horizontal sync interval between the lines.
3) The vertical interval sync signals between the video frames.
And there are actually several different kinds of vertical interval lines.

The entire waveform for a composite frame for a color video is quite large and almost certainly exceeds what an AWG could create.

And if you limit "waveform" to a single line of video, then you must accommodate more than one kind.
And I don't think most AWGs will handle that, either.

[Richard Crowley]

OTOH, you could use something like a Raspberry Pi to generate video signals rather easily.
And you could buy dozens of them for what even a cheap AWG would cost.

[JustAnotherGuy999]

thanks

[uncle_bob]

Hi

A good old analog TV set will not do much of anything with a single line of video. About the most simple is the old NTSC waveform that is essentially two frames that interleave. You get a full frame every 1/30 second. The signal can be looked at a number of ways and you get a different bandwidth each way. Just to move things on, let's say it's a 4.5 MHz bandwidth That gets you to something more than 9 mega samples per second. It would take a generator that will do a 100K sample run to do that.

Now, since it's an analog signal, you would need a very good lowpass filter between the generator and the TV. A more realistic setup would be about 20 mega samples per second and a somewhat easier to build filter. At that point you have a 200K sample generator. If you want to do it with the generator here on the desk and not play with a filter, you need to run a few mega samples through it. Oddly enough that's a bit more than this one will do.

Consider that none of this is actually synthesizing the waveform. All you are doing is playing back a digitized video signal. The only way you set it up is to do creative software to produce the file. You then just us the generator as a fast ADC to play your file. A $30 video card is a much easier solution.

Bob