Add DSP filters especially average filter

jopohl / urh

Universal Radio Hacker: Investigate Wireless Protocols Like A Boss

GNU General Public License v3.0

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Add DSP filters especially average filter #271

Closed HTRLo closed 7 years ago

HTRLo commented 7 years ago

Hi. I have used URH for some projects lately and the tool makes it easy to play with unknown protocols, great work! On my latest adventure in the RF world i need to tackle a GFSK signal. Is it possible to get GFSK as a modulation in UHR? I see that it is implemented in generator part of the SW, but not in the interpretation. Added a cutout of my troublesome signal for reference.

Regards Håkon

jopohl commented 7 years ago

Could you upload a part of your signal (.complex) so we can investigate?

HTRLo commented 7 years ago

Her is a capture of the signal.

Had to rename the zip file to PDF for GitHub to accept it. Just rename it back to .zip after download.

RTL-SDR-155_467MHz-2MSps-2MHz.pdf

jopohl commented 7 years ago

Thanks for the sample signal! We will have a look at GFSK demodulation support.

jopohl commented 7 years ago

Hi @HTRLo ,

I played around a bit more with your signal and found out, that there is a kind of quantization error. What I did, was to put a average filter on the signal giving me this: avg Does this look okay for you? I believe that URH can live without explicit GFSK demodulation support, as you can demodulate a GFSK signal by tuning the parameters in FSK demodulation as I did in the screenshot. However, I might be mistaken here! Here is the averaged signal for reference: averaged.pdf (rename to .complex after download)

If this works for you, we should think about integrating an average filter into Interpretation phase.

HTRLo commented 7 years ago

Ahh.. There is the signal ;) Tried on some other samples also, looks real promising. After some playing around i found out that 2 short pulses= binary 0 and 1 long pulse is binary 1. Now i need to try to regenerate the signal with my own bit stream to try some packet injection.