# simple composite video circuits

I am having a really hard time finding anything on the internet involving DIY composite video.

I can find multitudes of "Adapter" projects like VGA to Composite, S-video to composite ect... but no "how to generate a simple analog video waveform that my tv can understand."

I want to eventually design a circuit that amplifies guitar input and "converts" it into a analog video signal.

I feel like this could be an interesting project that could help others understand how signals work. I first need to learn how composite video works and I need somewhere to start, Any thoughts?

Thank you.

• Composite video is just a NTSC or PAL signal on a RCA connection. Commented Jul 16, 2017 at 22:18
• To get any sensible answers you should provide some data about how the TV picture depends on quitar's output. There's more than one relevant and artistically ambitious solutions, probably infinitely. You may see at least one of them, but we have no idea what it is. For example The screen can be full black when nothing is played. When playing, maybe you want something else. What and how it depends on something which is measurable from the signal? Can you give some photos or links to videos?
– user136077
Commented Jul 16, 2017 at 23:31
• The comment was maximally long. One relevant possiblity would be to input your guitar signal to an audio workstation which has a realtime spectrum display. Convert computer's monitor output to composite video.
– user136077
Commented Jul 16, 2017 at 23:45

An analog video signal is a very complex waveform. Getting any sensible video display based on a guitar's audio signal would be very difficult.

Look on Wikipedia for "Analog Television" for a description of the signal format.

A video image is drawn on the screen line-by-line. In North America, there are 525 horizontal line to make up an image (but some are hidden in the vertical retrace period). The horizontal scan rate is 15,734 Hz, with a vertical scan rate of 59.94 Hz (NTSC colour)(if I remember the numbers correctly). Odd lines of the image are displayed on one vertical scan, and even lines on the next.

• Yes i figured it would be a daunting task but I want the challenge. Read through the wiki and it is starting to make sense but I defiantly need some physical practice with circuits involving it. You guys have moved me in the direction I need to be in :) Commented Jul 17, 2017 at 6:08

Read this datasheet, which discusses the various horizontal and vertical pulses