[Coco] again: CoCo RGB to VGA conversion

[jdaggett at gate.net]

Mark

One major problem is that most modern monitors now will not do 15 KHz 
horizontal sync any more. I did come across a LCD monitor that did.

The AL 875 chip is the more promising of the lot. My only concern is that an 
8 bit ADC has only about 50  dB signal to noise ratio. While there literally 16 
milion colors, not all will look well. In reality many of the darker colors and 
hues will not be accurate due to potential noise issues. Secondary issues 
are that the input signal must stay within the range of the ADC. Thespeed of 
the ADC is  not a m ajor issue today as there are plenty of good quality 
ADC that  have sufficient speed for video. 

james

On 17 Aug 2004 at 21:23, Mark Marlette wrote:

Date sent:      	Tue, 17 Aug 2004 21:23:18 -0500
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From:           	Mark Marlette <mmarlett at isd.net>
Subject:        	Re: [Coco] again: CoCo RGB to VGA conversion
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> At 8/18/2004 04:11 AM +0200, you wrote:
> 
> Torsten,
> 
> I have done research on this project and it is in queue. SuperBoard
> will be finished before this is ever started though.
> 
> Mark
> Cloud-9
> 
> 
> >I'm still thinking about that task. This is for all you hardware guys
> >out there: Do you think it's possible to build a hardware for CoCo
> >RGB to VGA conversion out of these components:
> >
> >For 3-channel analog RGB -> digital RGB888 ADC:
> >
> >http://www.averlogic.com/password/AL875_Data_Sheets.PDF
> >
> >For digital RGB565 -> analog VGA conversion:
> >
> >http://www.averlogic.com/password/AL250_251_Data_Sheets.PDF
> >
> >Here's a design example:
> >
> >http://www.2k1.co.uk/products/averlogic/www1/AL250/AL875_250.pdf
> >
> >taken from this site which has more info:
> >
> >http://www.2k1.co.uk/products/averlogic/www1/AL250/
> >
> >Any comments welcomed.
> >
> >Torsten
> >
> >
> >--
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> 
> 
> 
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