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I want to measure spectrum Occupancy of any one of the GSM band using Gnuradio and a USRP for 24 hours.

Is there any way to save the waterfall plot of gnuradio in image file or any other format?

If not is there any other way to show the spectrum occupancy for certain amount of time in one image or graph?

Termininja
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John_R
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1 Answers1

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Is there any way to save the waterfall plot of gnuradio in image file or any other format?

Middle-mouse-button -> Save.

If not is there any other way to show the spectrum occupancy for certain amount of time in one image or graph?

This is a typical case for "offline processing and visualization". I'd recommend you just build a GNU Radio flow graph that takes the samples from the USRP, applies decimating band pass filters (best case: in shape of the GSM pulse shape), and then calculates the power of the resulting sample streams (complex_to_mag_squared) and then just saves these power vectors.

Then you could later easily visualize them with e.g. numpy/matplotlib, or whatever tool you prefer.

The problem really is that GSM spectrum access happens in the order of microseconds, and you want to observe for 24 hours – no visualization in this world can both represent accurately what's happening and still be compact. You will need to come up with some intelligent measure built atop of the pure occupancy information.

Marcus Müller
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  • thanks marcus, i ll see what can i do . i am very new to GnuRadio so i guess it will take time..but i will let you know if i succeed ... – John_R Aug 10 '16 at 06:50
  • I think saving the samples you're interested in to disk is the right thing to do. Pretty graphics are typically an offline-precessing thing. – Marcus Müller Aug 10 '16 at 07:13
  • from example code of gnuplot "usrp_spectrum_sense.py" ,we can save time ,freq, power etc . Is there any way to plot the waterfall plot from these data ?? any offline waterfall plotter ?? – John_R Nov 02 '16 at 11:34
  • @John_R yes. I mentioned numpy/matplotlib in my answer for a reason :) – Marcus Müller Nov 02 '16 at 11:38