Re: [Discuss-gnuradio] "video" transmitter

[Tim Pozar]

Very cool!

Tim

On Mon, Feb 02, 2004 at 04:50:40PM -0800, Matthew Kaufman wrote:
> Inspired by the FCC proceedings regarding regulation of D/A converters, I
> spent this morning writing software, the idea of which may be of interest to
> this group.
> 
> Runs under Windows (why? Because that maximizes the number of preinstalled
> demo platforms), turns your computer into a radio transmitter. Using the
> data contained in a .wav file, modulates your video card as an AM or FM
> transmitter by stuffing bits rapidly into the framebuffer (triple-buffered,
> uses DirectX/DirectDraw). No real UI yet, just a prototype to prove that it
> can be done (which it can, albeit somewhat crudely and with audible
> artifacts from vertical blanking). My 1200 MHz K7 machine can do AM and FM
> audio at 5-7 MHz no problem (using 640x480x60 Hz), and test tones (can't
> update the buffer fast enough for good sounding live audio) all the way up
> into the FM broadcast band (1600x1200x90 Hz gets a decently high dot clock)
> 
> If, for some reason, someone wanted to prove a point about why regulating
> DACs is silly given that every computer with VGA or better video can be a
> transmitter, drop me a note and we can put together something that's
> demoable.
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