Date   : Sat, 04 Feb 2012 22:17:02 +0000
From   : beeb@... (Kris Adcock)
Subject: RGB to mono composite with only resistors

LONG ago in the distant past, I had a need to convert the RGB signals 
from (I think) a Teletext podule into a composite video feed. I only 
needed mono, so someone supplied me with a simple circuit diagram (I'm 
pretty sure that it used ONLY resistors) and combined everything 
together into composite video.

I'm guessing that the different resistors gave each of the colour 
channels a different bias that made sense in mono (red is more prevalent 
than blue, etc).

Unfortunately I can't find the e-mail, my notes, or remember who 
supplied me with this information. Has anyone here done this, or did I 
dream it all?

Many thanks in advance,

Kris.