[Discuss-gnuradio] VGA-based DVB-T modulator

[Seth David Schoen]

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)