> Date: Fri, 7 Jul 2017 19:50:55 +0300 > From: HLL > Hi all, > > I'm relatively new to DSP and gnuradio but I tried tons of stuff and > I couldn't decode a fairly simple FSK data. > baudrate seems around 600-700 bps and fsk deviation is less then 3k.
Hmmm. I took a look at your signal and tried building a coherent 2-FSK demodulator. Under the assumption that it was straight 2-FSK, the signaling tones looked to be at +/- 1200 Hz when properly centered. The fastest bit rate appeared to be 1880 bits/sec. But in reality that doesn't work. I could never get good symbol timing recovery as the "FSK" signal appeared to have two different baud rates. After some reflection, the signal you have appears to actually be AFSK inside of FM. Zoom out a little on the output of the quad demod, and your eye can see the two tones. The two tones appear to be at 350 Hz and 940 Hz. The tones are unusual in that they are square wave tones vs. sine wave. I haven't worked you the baud rate yet. I'll hack away at it more tomorrow. Regards, Andy > > Thanks for the help > HLL. _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
