When I first saw the video by Charles Lohr (a certified genius IMO) I had to spend several minutes trying to get my head around what he had done.
Using the DAC he bit bangs a signal at just the right frequency to match NTSC channel 3 which gets picked up as a TV/radio signal by the TV and displays it. Charles ensures the bits that generate the radio signal match the requirements of the NTSC spec.
Then he displays 3d graphics over that NTSC broadcast signal. Then he adds NTSC color.
That is software defined broadcast television. Mind. Blown.
I started collecting old TV's being dumped out the front of houses for hard waste collection after I saw that video, so I could give it a try.
It's not precisely broadcast, it's in the "baseband" region and would require modulation up to RF frequency to actually transmit over a distance.
See earlier work by Fabrice Bellard: https://bellard.org/dvbt/ (arguably more impressive signal processing, but requires a graphics card's high-speed DAC)
30 to 300MHz still has the ITU designation of "very high frequency". I know that these days all the sexy stuff is microwave, but the EM spectrum is useful all the way down to DC. The cave radio system used in the rescue of the Wild Boars operates down at 87 kiloHertz. Surface-to-submarine radio systems all operate below 30kHz.
> is able to generate a wireless NTSC video signal
But then I read
> is able to generate a broadcast TV signals
and I read it again.
Are you telling me this will actually produce a RF signal that could be picked up by a 80s era portable television?
That is indeed amazing and I actually wouldn't have thought it possible with a digital device.
EDIT - Having just watched that video I can say that is truly amazing. That has made me so happy.