[Coco] Using a PC monitor on the CoCo

Bob theother_bob at yahoo.com
Thu May 20 00:07:50 EDT 2004

--- Allen Huffman <alsplace at pobox.com> wrote:
> On May 19, 2004, at 10:17 PM, Bob wrote:
> > You might look at the new LCD screens out... there is a notion
> > that some of these may sync to the CoCo3's RGB-A signal. I would
> > tend to expect it to work, but good luck finding out for sure.
> Why would that be?  What else syncs to 15hz?
> I did find out that the video output of my Atari Jaguar is also 15hz.  
> So, we should be able to use any solution that has been done for Amiga, 
> some Atari STs, and Atari Jaguar machines.  Anything else take the same 
> RGB type video?
Analog component video is still in wide use for video production, although
digital is trying to replace it. 
A lot of DVD players, etc. now have RGB component outputs and I believe some
TV's have component inputs. These would be 15KHz, sync on green.
An LCD screen which can display VGA or S or composite video has all the needed
circuitry to do what we need, it's just a question of did the designers allow
it to work that way?

My thinking is as follows: normally to display NTSC video on a VGA monitor you
have to 1)separate the composite video into RGB, 2)A/D sample it, 3)store it,
4)D/A it back out at twice the rate.
 If I'm an engineer designing an LCD monitor, trying to minimize parts count
and reduce costs, it's a lot easier to eliminate the three steps of scan
doubling and just allow the thing to sync to the lower rate, right?


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