[opendtv] Re: Create DVB-T RF with your VGA card

  • From: "John Willkie" <JohnWillkie@xxxxxxxxxxxxx>
  • To: <opendtv@xxxxxxxxxxxxx>
  • Date: Tue, 21 Jun 2005 11:24:50 -0700

less than the 3K that Computer Modules will sell one to you for?

John Willkie
----- Original Message ----- 
From: "Adam Steinberg" <adam@xxxxxxxxxx>
To: <opendtv@xxxxxxxxxxxxx>
Sent: Tuesday, June 21, 2005 10:20 AM
Subject: [opendtv] Re: Create DVB-T RF with your VGA card


> Hell, I'd even pay some money for a low cost 8VSB signal generator like
> that.
>
> Adam
>
> -- 
> Adam Steinberg
> Director, Product Line Management
>
> Elgato Systems LLC
> 900 Kearny Street Suite 750 San Francisco, CA 94133-5145
> T 415/391-0310 x235 F 415/391-0329 www.elgato.com
>
>
> On 6/21/05 9:57 AM, "John Shutt" <shuttj@xxxxxxxxx> wrote:
>
> > Any takers on the 8-VSB hack?
> >
> > John
> >
> > <http://www.tvtechnology.com/dlrf/one.php?id=910>
> >
> > Don Lung's RF Report
> >
> > Use Your PC VGA Card to Generate DVB-T RF
> >
> > Although I haven't been able to verify this actually works, I thought
> > readers would be interested in a Web site describing how to use a PC
running
> > Linux and a current generation video card to create a modulator capable
of
> > generating a VHF DVB-T signal. At present, the system does have some
> > limitations. It can only transmit still images and the DVB-T signal
> > containing the images has to be computed separately before it is sent to
the
> > VGA adapter.
> >
> > If you are interested in trying out this modulator, you will need a PC
with
> > a recent VGA card able to display resolutions up to 4096x2048 using 8
bits
> > per pixel with a pixel clock of exactly 76.5 MHz. The ATI Radeon 9200SE
> > cards are reported to work, according to the Web site. The video card's
red
> > digital to analog converter output (signal pin 1 and ground pin 6 on a
> > standard 15 pin VGA connector) is used as the RF output. The output
power is
> > very low so you will likely need to make a cable to feed the RF to the
TV
> > set.
> >
> > The DVB-T modulator also requires use of Linux and the X Window system
on
> > the PC. The X Window server allows custom configuration of the video
card's
> > output signal. Using precompiled files from the Web site, you can
generate a
> > valid 16-QAM DVB-T COFDM-2K output signal receivable on channel 5
(178.75
> > MHz) with two channels, each with a still picture.
> >
> > For details on this interesting experiment, files, and additional links,
see
> > Use your VGA Card to Transmit DVB-T signals! A Low Cost Analog and
Digital
> > TV (DVB-T) Modulator. <http://fabrice.bellard.free.fr/dvbt/>
> >
> > Who will be the first to use similar techniques to generate an 8-VSB
signal
> > on a U.S. TV channel using a video card? As the 8-VSB signal is less
complex
> > than the COFDM signal, it seems this wouldn't be too difficult! If you
> > succeed, please let me know! As we make the transition to digital TV,
there
> > will be a need for low-cost test equipment and ideas like this that
> > challenge engineers to learn more about DTV transmission.
> >
> >
> >
> >
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>
>
>
>
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