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[Discuss-gnuradio] VGA-based DVB-T modulator
From: |
Seth David Schoen |
Subject: |
[Discuss-gnuradio] VGA-based DVB-T modulator |
Date: |
Mon, 13 Jun 2005 14:05:32 -0700 |
User-agent: |
Mutt/1.5.9i |
Someone proposed this a while ago, but Fabrice Bellard (who is also
responsible for cool stuff like the tcc compiler, which lets you use
C as a scripting language and lets the Linux kernel compile itself
at boot time) has used a VGA card's DAC as an RF modulator to produce
a valid DVB-T signal.
He uses a static greyscale image displayed under X11 with weird video
timings, and connects two of the VGA pins to a coax cable.
It generates a DVB-T signal on DVB-T channel 5 in VHF (around 176
MHz). He has also produced PAL and SECAM VHF equivalents by the same
technique.
http://fabrice.bellard.free.fr/dvbt/
(via slashdot)
So it looks like you can use a VGA card as a source of arbitrary VHF
waveforms (at least arbitrary periodic VHF waveforms) without an
upconverter. Bellard seems to think that you could use it to do
nonperiodic waveforms too.
--
Seth David Schoen <address@hidden> | Very frankly, I am opposed to people
http://www.loyalty.org/~schoen/ | being programmed by others.
http://vitanuova.loyalty.org/ | -- Fred Rogers (1928-2003),
| 464 U.S. 417, 445 (1984)
- [Discuss-gnuradio] VGA-based DVB-T modulator,
Seth David Schoen <=