[Discuss-gnuradio] fft monitoring of more than one channel

2012-02-08 Thread Sebastian Döring

Hello list,

I modified the usrp_spectrum_sense.py to work as an energy 
detector based on the Neyman-Pearson Theorem. So basically 
the algorithm is supposed to tell me if a certain part of 
the spectrum is occupied or not.


I simply wrote the output into a text file to see I it is 
working at all, but right now I am trying to find a way to 
somehow monitor the it in a large plot, that dynamically 
changes with the current detection results.
That means that if I am sensing the spectrum for example 
between 2.4 and 2.5GHz in steps of 20MHz, I want the the 
whole bandwidth to be graphically displayed in some kind 
of plot (x-Axis = frequency, y-Axis = 0/1), which is 
divided into parts of 20MHz.
The channel states are supposed to get updated every time 
the channel is sensed again, just like the output is 
already doing.


I first thought that gtgui_sink_x might be the right 
thing, but since I am peridically changing the frequency 
and the sink is designed to look at a single center 
frequency, I don know how to append several frequency 
windows to a large one.
I dont know if what I am planning to do is even possible 
using gnu radio only.


I higly appreciate any suggestions.
Thanks in advance.

-Sebastian

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Re: [Discuss-gnuradio] fft monitoring of more than one channel

2012-02-08 Thread Tom Rondeau
On Wed, Feb 8, 2012 at 8:19 AM, Sebastian Döring sdoer...@rhrk.uni-kl.dewrote:

 Hello list,

 I modified the usrp_spectrum_sense.py to work as an energy detector based
 on the Neyman-Pearson Theorem. So basically the algorithm is supposed to
 tell me if a certain part of the spectrum is occupied or not.

 I simply wrote the output into a text file to see I it is working at all,
 but right now I am trying to find a way to somehow monitor the it in a
 large plot, that dynamically changes with the current detection results.
 That means that if I am sensing the spectrum for example between 2.4 and
 2.5GHz in steps of 20MHz, I want the the whole bandwidth to be graphically
 displayed in some kind of plot (x-Axis = frequency, y-Axis = 0/1),
 which is divided into parts of 20MHz.
 The channel states are supposed to get updated every time the channel is
 sensed again, just like the output is already doing.

 I first thought that gtgui_sink_x might be the right thing, but since I am
 peridically changing the frequency and the sink is designed to look at a
 single center frequency, I don know how to append several frequency windows
 to a large one.
 I dont know if what I am planning to do is even possible using gnu radio
 only.

 I higly appreciate any suggestions.
 Thanks in advance.

 -Sebastian


If you want to show the whole spectrum in one qtgui window, it's going to
take a bit of hacking.

On the other hand, you can probably just use the qtgui right now. The block
just takes in the data sent to it and plots it, regardless of where it came
from. The center frequency of the plot is just for reference and doesn't
have any real meaning for the data planned. This will only show a section
of the full bandwidth at a time, but it might be enough to get you started.

Tom
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