The good news is. the GFSK block doesn't do anything specific to Gaussian FSK. So I guess tha tall works out =)
You're outputs might be more illustrative if you rebuild it in from the blocks actually inside the GFSK demod block: quad demod > clock recovery -> slicer On Fri, Oct 17, 2014 at 12:33 PM, Luke Berndt <l...@robotastic.com> wrote: > It actually looks like the control channel for Motorola SmartNet is FSK: "On > the control (data) channel the base station transmits 84 bits frames at > 3600 bit/s with direct frequency modulation of the carrier using Frequency > Shift Keying (FSK). " > > I will at least see if I can get something that looks right out the other > side. Would it be best to use one of the GFSK examples in gr-digital? > > On Fri, Oct 17, 2014 at 10:37 AM, John Malsbury < > jmalsbury.perso...@gmail.com> wrote: > >> Also, my understanding for the PLL blocks were that they were ideal for >> "strong carrier" signals like AM. When I say strong carrier i mean a >> signal that has an obvious carrier which isn't "hidden" under modulation.. >> >> Anyway, the GMSK block might be a good place to start. >> >> -John >> >> On Fri, Oct 17, 2014 at 7:35 AM, John Malsbury < >> jmalsbury.perso...@gmail.com> wrote: >> >>> It doesn't have frequency correction - I can probably follow up with >>> some ideas on how to implement that part. But the GMSK demod might do OK >>> for you initially. It doesn't do anything intelligent to deal with the >>> data shaping - its just a non-coherent slicer. >>> >>> If you want to design in GRC but keep your top-level application as is, >>> you can use a hier block. You can also use a command line parameter or >>> other mechanism to select your demodulator at start-time for easy >>> comparisons. >>> >>> [typed one handed.. my daughter has my other and] >>> >>> -John >>> >>> On Fri, Oct 17, 2014 at 7:08 AM, Luke Berndt <l...@robotastic.com> >>> wrote: >>> >>>> Thanks for looking into it! To be honest, I am not really good at RF. I >>>> based my code off the python code in gr-smartnet. The fsk-demod python file >>>> is here: >>>> https://github.com/bistromath/gr-smartnet/blob/master/src/python/fsk_demod.py >>>> >>>> It is quite possible that it just happened to work because of an error >>>> that got patched in Gr 3.7. >>>> >>>> Are there some good examples for GMSK/FSK demodulation that I could >>>> borrow from instead? >>>> >>>> Recreating this in GRC sounds like a great idea so I can scope along >>>> the way. I will give that a try next. >>>> >>>> Thanks again for the pointers, fresh eyes are really helpful when you >>>> have been staring at it for so long. >>>> >>>> - Luke >>>> >>>> On Fri, Oct 17, 2014 at 8:18 AM, Martin Braun <martin.br...@ettus.com> >>>> wrote: >>>> >>>>> On 10/17/2014 08:28 AM, John Malsbury wrote: >>>>> > Also also, is the Band-Edge FLL ideal for GMSK? My possibly, >>>>> incorrect >>>>> > understanding of that block is that it was more ideal for PAM with >>>>> > common RRC. >>>>> >>>>> For the record: It might work coincidentally because of the rolloff-y >>>>> shape of GMSK, but it's derived for and designed for common PAM/RRC, as >>>>> John says and I wouldn't recommend it for anything else. >>>>> To look up the math, I suggest Harris' works. >>>>> >>>>> >>>>> >>>> >>>> _______________________________________________ >>>> Discuss-gnuradio mailing list >>>> Discuss-gnuradio@gnu.org >>>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >>>> >>>> >>> >> >
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