[Discuss-gnuradio] Simple gr goodies - audio filter and scrambler

[Chuck Swiger]

Gang - Here's a couple of simple application that use no hardware other than an
audio card. I'm really suprised the scrambler works but the tools make it 
pretty easy.

Audio Filter - specify low freq, high freq and width of skirts (steeper 
skirts = more cpu)
e.g. $./filter.py 400 1800 100   for very constricted audio:

Audio scrambler - multiplies the audio stream with gaussian noise, saving 
both noise
and product to two files. Verify the product file is unintelligible. 
Descramble by dividing
the product file by the noise file and get intelligible audio back.  Run 
$./scramble.py and
hit enter when done recording. Play the scrambled audio with $./play.py to 
verify it's
noise. Descramble with ./$descramble.py plays the audio.

Both projects are at: http://www.widomaker.com/~cswiger/gnuradio/

--Chuck