Convert composite (fixed scan) signal to PC

[TerminateDrone]

I have a color video monitor with a 2xBNC connection for input. I believe this to be a composite input (although not 100% sure - maybe someone with experience with video monitors can correct me). I'm looking for a circuit to convert the signal to VGA or even better, to S-Video so that it can be used through a video card on a PC.

There are video cards available for a similar task to this: http://www.mirage-mmc.com/ but I figured I should look for a DIY way before settling on the card, because 1. It'll be a good learning experience, and 2. It'd require a different video card and drivers to use the card, which would add complexity to my project.

I'd greatly appreciate if someone would take the time to explain what would be required to do this conversion. It seems to me that S-Video to composite has many easily available cables and adapters. Something like http://www.hollyhand.com.tw/INDEX/webhtml/750H1795-1.htm for example. But for some reason I get the fealing that this is not what I need. Is there anyone here who has used professional video monitors with 2xBNC connectors that can explain what exactally is required to send the video signal to the monitor?

Thanks in advance,

Dan

 

[Nigel Goodwin]

I'm not entirely sure what you're wanting to do? - is it to use this monitor as your PC monitor?.

There are a number of problems with this, firstly the resolution of a video monitor is FAR! less than a PC one - so picture quality is likely to be far inferior to a proper PC monitor.

But more importantly, the specification is COMPLETELY different - a PC monitor works at more than twice the line frequency of a video monitor, and often more than three times the field rate.

In order to do it, you first need to run your PC at a low resolution (often only VGA 640x480), and have a video card that will output a video signal.The video card contains the hardware to do the required standards conversion, which never works terribly well!. Personally I've always had loads of trouble making them work!, and when they do the picture quality is still pretty poor.

As for the two sockets on the monitor, they could be for various reasons? - often you have a video IN, and a paralleled socket for looping OUT to another monitor. Or they might even be video and seperate sync inputs?.

 

[TerminateDrone]

Sorry, I appologize for not being more clear.

I'd just like the ability to test the monitors with software on the PC.

I figure I could take an S-Video adapter, and connect the video signals into 1 BNC socket, and this would work if it was composite signal (In/Out). But after racking my brain trying to figure out the stupid connection for so long, it better not be that simple. I guess I was just confused because I was expecting something more complex (like 3xBNC with sync on green).

However, if as you said, one socket has video information while the other is sync I would need some sort of a conversion circuit. https://www.epanorama.net/circuits/vga2rgbs.html Under the title "Simple sync combining BOX" has a circuit that seems to do this.

Give me a couple days and I'll try to figure out what it needs.
Thanks for the help.

Dan