[Coco] Converting CoCo 2 and CoCo 3 to Component video?

[jdaggett at gate.net]

John

Essentially that is correct. The drawback is that the MC6847 has 
only has 2 bit DACs internally for the R-Y and B-Y signals and Y 
level is 3 bits. 

The thing is Component video is essentialy the modulation signal 
for the RF carrier like channel 3 or 4. COmponent video is not some 
new fangled system. All component video is are the Luminance and 
Chroma signal that would go to an RF modulator are brought out 
the back of the unit and distributed. 

Converting a Coco1 or 2 to component video would gain no 
additional color but may gain a better qulaity picture. At least there 
is no RF to demodulate and all that.

james


On 2 Nov 2004 at 13:09, John Kowalski wrote:

To:             	CoCoList for Color Computer Enthusiasts 
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From:           	sock at axess.com (John Kowalski)
Subject:        	[Coco] Converting CoCo 2 and CoCo 3 to 
Component video?
Date sent:      	Tue,  2 Nov 2004 13:09:43 -0500 (EST)
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> James Daggett wrote:
> >
> >... at any instance of time the color signal can be
> >broken into four components Luminace, and three chrominance
> >signals R-Y, G-Y and B-Y. The three needed components for color
> >transmission are as follows: 
> >
> >Y	luminance
> >B-Y	Blue minus Luminance or Chrominace A
> >R-Y	Red minus Luminance or Chrominace B
> >
> >The Y signal is governed by the following formula
> >
> >Y = 0.3*R + 0.59*G + 0.11*B
> >...
> >
> >... Oddly enough these are the same signals that come out of the
> >MC6847 VDG chip used in the Coco 1/2; Y, R-Y and B-Y.
> 
> Does that mean that we could pretty much directly hook up a CoCo 1 or
> 2 to a modern component-capable TV and get a superb picture?  How
> complicated would it be to do?
> 
> I remember way back people used just the Y signal for monochrome
> monitors. Now we could also use the R-Y and B-Y lines for full color,
> right?
> 
> It's too bad CoCo 3 video isn't as convenient to convert.  Some time
> ago I was interested in trying to convert the CoCo 3's RGB into
> component video, but I only found complicated looking schematics for
> the conversion at the time.  But it should be a fairly simple circuit,
> shouldn't it?
> 
> This sounds like a simpler, more elegant solution than trying to
> convert CoCo 3 RGB into VGA.
> 
>                                    John Kowalski (Sock Master)
>                                    http://www.axess.com/twilight/sock/
> 
> 
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