Re: Once upon a time, there was a device...

["Vince Briel" <vbriel@removethisspamcamcast.net>]

I personally don't have a RGB monitor on a GS but there is a chip made by 
Averlogic and I think that does RGB to VGA conversion (scan doubling). Can't 
vouch for the picture quality but it should do the job. Problem is, it is 
surface mount and that means no hobby builders.

Vince

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"Michael J. Mahon" <mjmahon@aol.com> wrote in message 
t-WdnammZeaXDw3ZnZ2dnUVZ_qmdnZ2d@comcast.com">news:t-WdnammZeaXDw3ZnZ2dnUVZ_qmdnZ2d@comcast.com...
> Jon wrote:
>> Hehe,
>> This topic seems to eternally come in and out of the group :D.  Is
>> there a way do make a DIY circuit to convert the RGB to component ?  or
>> maybe there's an off the shelf chip that does that already and all you
>> got to do is connect the wires to it?
>
> Yes, it seems ripe for inclusion in the FAQ, if it's not already there.
>
> Component video is just a re-encoding of the RGB signals, complicated
> slightly by the need to add composite sync to the Y signal.
>
> All of this is pretty simple analog circuitry, involving three or four
> video opamps, which are now a dime a dozen.  Many of them are rail-to-
> rail, so they only need a +5v supply (present on many RGB connectors).
>
> I published a URL for an manufacturer's appnote on this three years
> ago, but it seems to have gone dead.  A URL to a .gif of a similar
> circuit (for VGA in, therefore needing to create composite sync)
> appeared in this forum recently.
>
> Altogether, a triple- or quad- video opamp and a dozen resistors and
> a couple of decoupling capacitors would do the job, so the cost should
> be under $10.  Of course, a box, connectors, and labor could run that
> up some, but the $100+ boxes being sold that do exactly the same thing
> are clearly priced for the "home theater" market.
>
> -michael
>
> Parallel computing for 8-bit Apple II's!
> Home page:  http://members.aol.com/MJMahon/
>
> "The wastebasket is our most important design
> tool--and it is seriously underused."