The Cyber-Spy.Com Usenet Archive Feeds Directly
From The Open And Publicly Available Newsgroup
This Group And Thousands Of Others Are Available
On Most IS NNTP News Servers On Port 119.
Cyber-Spy.Com Is NOT Responsible For Any Topic,
Opinions Or Content Posted To This Or Any Other
Newsgroup. This Web Archive Of The Newsgroup And
Posts Are For Informational Purposes Only.
From: Richard Dungan
Subject: Re: Help? Ways to build RGB divider to NTSC UHF transmitter?
Date: Wed, 13 Nov 2002 18:25:19 +0000
Organization: Radix Electronic Designs
References: <email@example.com> <3DD17E5A.firstname.lastname@example.org>
X-Newsreader: Forte Agent 1.92/32.572
NNTP-Posting-Date: Wed, 13 Nov 2002 18:25:19 +0000
Dan Barlow wrote:
>> I want to take a 1600x1200 rgb signal. cut it into to 320x240 pieces.
>> Then broadcast each piece to a separate uhf channel.
>> What's the easiest way to do something like this. How much would it
>> cost to prototype such a device.
>> right now it's for a science project at my school, and I'll be seeking
>> grant funding to build it.
>It would be very hard to do this in the way you describe.
>First you would need very fast Analog to Digital converters
>to sample the source RGB. In the range 250 - 300 MHz I would think.
>Then you would need a frame buffer for each output, and a NTSC encoder
>for each output. The logic to steer the samples coming in at 300
>MBytes/sec * 3 channels will have to be extremely well laid out.
>You might need to double-buffer each output to allow one buffer to be
>filled at high speed while the other is output at NTSC speed.
>Hmm, you might be able to do it all in a fast FPGA with outboard
>static RAM and ADCs and daughterboards for the outputs...
>I think you would be better off buying a quantity of TVout
>cards and doing the image breakup in software. You can get
>video cards with up to 8 VGA outs and do vga to TV with an
>external box... but you're looking at 25 outputs so it will
>get expensive whichever way you look at it.
As Dan B. says, this is not a project for the faint-hearted. My
suggestion is that you get your digitizer ready-made as an LCD
controller. DigitalView sell suitable products although here in the UK
their customer sevice beggars belief. There are others.
After that, Dan B is pretty well on the money. A fast FPGA, emulating an
LCD input, for mapping and timing, and some dual port RAMs to buffer the
sub-displays. AFAIR you can download suitable FPGA design software from
both Altera and Xilinx. The dual-port RAMs could come from IDT, among
Then, fast ADCs and ready-made NTSC modulators (Astec?) to generate your
I hope this helps.
Richard (who has been involved with something similar)
I may be able to help more if you email me privately, avoiding the spam
Radix Electronic Designs, Orpington, UK
Go Back To The Cyber-Spy.Com
Usenet Web Archive Index Of
The sci.electronics.design Newsgroup