[Coco] New s-video board for the CoCo3 RGB port

Gene Heskett gheskett at wdtv.com
Sun Apr 10 13:56:41 EDT 2016

On Sunday 10 April 2016 09:28:40 Joe Grubbs wrote:

> Wow those look exceptional! Excellent work Ed

To me, that is not surprising, s-video format, which is the luminance 
sent to the monitor on one piece of coax, and the encoded color 
subcarrier on another, never mixed, removes the need to filter and 
separate them in the tv/monitor. Since the coco output is NOT 
interlaced, that delicate timing that makes a "comb" filter work, 
doesn't work for the coco's composite output.

The thing that does impress me is that its sharper by a considerable 
amount than my gime chip is capable of outputting to a real RGB monitor 
with a 20 megahertz video bandwidth, yet you are plainly using the 
buffered gime output.  Those character edges are far sharper than the 
140 ns rise and fall times my gime can do, I'd guestimate Ed, that a 
scope on that video would show rise & fall times, that are half, or even 
less of what mine can do.

s-video inputs on monitors are not universal, but seem to be much more 
available on the ones sold as tv's. When I have bought new digital tv's, 
one of the must haves is an s-video input as I have dvd players and an 
S-vhs tape recorder with s-video outputs.

> ________________________________________
> From: Coco <coco-bounces at maltedmedia.com> on behalf of Zippster
> <zippster278 at gmail.com> Sent: Saturday, April 9, 2016 10:29 PM
> To: CoCoList for Color Computer Enthusiasts
> Subject: [Coco] New s-video board for the CoCo3 RGB port
> Hello everybody,
> I’ve put together a composite and s-video adapter for the CoCo3 RGB
> port. I had a chance to put together some prototype PCBs I received
> back, and it’s looking pretty good.
> The s-video output in particular is excellent.  Very useable 80 column
> text screen and nice graphics screens for games.  Here is a link to
> some pics of the board and some screen shots.  The screen shots are
> all s-video on a 50 or so inch LCD TV.
> <https://drive.google.com/open?id=0B1sgl615FlGneHZWa2VhbUJWcEE
> <https://drive.google.com/open?id=0B1sgl615FlGneHZWa2VhbUJWcEE>>
> - Ed
> --
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> Coco at maltedmedia.com
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Cheers, Gene Heskett
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>

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