/vr/ - Retro Games

What's the best solution to converting rf into a signal that a pvm can take. I know most consoles by now have a rgb or s-video card, but I also have some rather obscure consoles I'd like to run on my pvm, and was hoping I could get a hold of a rf demodulator or something with better results, that output a decent signal. I know when it outputs rf it's pretty much a moot point, but I'd like to find a way to get it on there without further obscuring the picture.