Thanks a lot. I'll read the block specifications. And yes, the offset is small (120 kHz).
Em qua., 24 de jun. de 2020 às 17:53, Jeff Long <willco...@gmail.com> escreveu: > Assuming the difference is small enough, this is a normal RX problem that > a GMSK demod should be able to handle. The labels on your frequency plot do > not say what the offset is, but hint that it is small. Take a look at > gmsk.py > <https://github.com/gnuradio/gnuradio/blob/b76e8788687b4feef610e501c0c7d167c4f04a98/gr-digital/python/digital/gmsk.py#L165> > to > see how it's handled in the built-in demod. > > On Wed, Jun 24, 2020 at 4:10 PM Artur Nogueira <artur.no...@gmail.com> > wrote: > >> Hi Jeff, >> >> Thanks for the feedback. >> I'm using GNU Radio Version 3.7.13.5 and two Great Scott Gadgets HackRF >> units for the transmission/reception. >> My workflow looks like this: >> >> [image: image.png] >> >> Do you usually use any artifact to compensate for this frequency shift? >> I'm afraid this could affect demodulation and therefore the BER. >> >> Best regards, >> Artur >> >> >> Em qua., 24 de jun. de 2020 às 16:31, Jeff Long <willco...@gmail.com> >> escreveu: >> >>> Artur, >>> >>> You haven't mentioned what software you are using, how you have it >>> configured, or what your flowgraph looks like. >>> >>> If you are using two SDRs and the frequency difference is a few kHz, >>> then that is just oscillator differences. >>> >>> On Wed, Jun 24, 2020 at 3:12 PM Artur Nogueira <artur.no...@gmail.com> >>> wrote: >>> >>>> Hi everyone, >>>> >>>> I'm comparing the spectra of a pair of transmitted/received GMSK >>>> signals (carrier frequency = 923 MHz). >>>> As expected, there is a certain channel attenuation. >>>> Nevertheless, there is this frequency deviation at the Osmocom Source >>>> output: >>>> [image: image.png] >>>> >>>> I suppose this is something related to the receiver hardware. >>>> Do you have a suggestion on how to compensate for this effect at a >>>> software level? >>>> >>>> Best regards, >>>> Artur >>>> >>>>
