For anyone working with APRS Stephen (wa8lmf) has put together a downloadable cd image with a lot of test data. Not in quadrature, but that's maybe something Hilbert can take care of.
http://wa8lmf.net/TNCtest/ # Get it with wget. $ wget http://www.argentdata.com/files/tnc_test_cd_ver1.0.zip # Convert the tracks to wave format with the bchunk utility (search your packet manager or homebrew). $ bchunk -w TNC_Test_Ver-1.1.bin TNC_Test_Ver-1.1.cue TNC_Test_Ver-1.1.iso --Albin On Mon, Dec 28, 2015 at 2:07 AM, En Shih <[email protected]> wrote: > Thanks, Tim. That really clarified a lot of confusion that I had! > > I have uploaded the files here: > https://drive.google.com/folderview?id=0B5T4PFVUKZgmcXlTWnV0VzZFQTg&usp=sharing > <https://drive.google.com/folderview?id=0B5T4PFVUKZgmcXlTWnV0VzZFQTg&usp=sharing> > -"bell202new.grc" is the current flow graph. > -"dump" is how the input signal I'm trying to decode looks like. > -"decoded" is the bytes of a successfully decoded signal, which was decoded > previously using some hardware equipment. (some parts of the data may be > corrupted) > -"imet.pdf" explains the data packet. > -"tcp.py" explains the data packet. > > As far as I know, at the physical layer the data is modulated using Bell > 202. The data framing is not AX.25, but conforms to UART, although I'm > unsure about the parity and stop bits. I tried looking for the data frames > by looking for start/stop bits, the header. I've also tried flipping the > bits. However, it still doesn't look quite right. > > Correct me if I'm wrong: your FSK demod block uses tone detection to > demodulate, which is passing the signal through two band pass filters in > parallel, and determine which comes through (as in p.9 of > http://edge.rit.edu/edge/P09141/public/FSK.pdf) > > Regards, > En Shih > > > > > -- > View this message in context: > http://gnuradio.4.n7.nabble.com/Help-decoding-Bell-202-tp57483p57503.html > Sent from the GnuRadio mailing list archive at Nabble.com. > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio _______________________________________________ Discuss-gnuradio mailing list [email protected] https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
