On Jul 2, 3:11*am, Antti <Antti.Luk...@googlemail.com> wrote:
> It is really possible to use FPGA to generate FM Radio signal DIRECTLY
> in most cases there radio will pickup signal from PCB trace already
>
> i did only a very little experiments (wrote in june issue also a
> little)
>
> even using audio signal to invert phase will produce signal that is
> received
> as FM modulation (with low modulation index) using simple NCO gives
> much better results.

Interesting, but it will have a fat spectrum...?
You could get (somewhere) into the FM band easily enough with a ring
oscillator,
and the average frequency could tell you the die temperature
Modulate one gate in that chain,and you get FM,
Modulate Vcc, and you also get FM ...

Next thing to do, is look at the Traffic Data information some radios
can
receive, and send real messages to your FM radio...
You could give the spooks a real fright with that one..

-jg