On Sun, 2016-03-27 at 14:03 -0400, Andy Walls wrote: > On Sun, 2016-03-27 at 12:00 -0400, [email protected] > wrote: > > > > Message: 5 > > Date: Sat, 26 Mar 2016 15:05:02 -0400 > > From: Andy Walls > > > > From: > > > Tom Golden > > > Subject: > > > Re: [Discuss-gnuradio] Ettus N210 > > > GMSK 9600 > > > Date: > > > Sat, 26 Mar 2016 10:12:18 -0600 > > > > > > I've been staring at the de-modulator and I really think it's > > correct. > > > Unfortunately amateur packet radio isn't well documented (at least > > for > > > me). > > > > > > > > > I think there's a scambler I'm not taking into account. Does anyone > > > know the specifics of this? Or can point me to how to what the > > > parameters of the descrambler block mean and/or how to determine > > their > > > settings (my best guess is it's a 17-bit LFSR with a polynomial of 1 > > > +x^12+x^17)? > > > > > > I can't help with the descrambler, sorry. There are some AX.25 pages > > out there that talk about it; you've probably seen them already. > > I was able to figure out the descrambler. :) > > The attached flowgraph now has the HDLC deframer spewing out test data > packets full of 0x44's.
Oopsie. Flowgraph attached for real this time; not just the generated python. -Andy > The radio appears create a pretty long idle stream (repeated HDLC flags) > at the start of a burst. > > Regards, > Andy >
gmsk9600_test2.grc
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