Forum: GNU Radio spectrum analyzer

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Fca804b8911d5b7f567921b301595160?d=identicon&s=25 Abram Young (Guest)
on 2007-06-13 18:08
(Received via mailing list)

I'm a recent gnuradio/python user (newbie) and have played with the
pieces and USRP as far as time will allow for now.  I can write my own
program to record A/D streams to disk, but that's about it.  I'm using
Octave to read in and plot the streams then.

I'd like to either modify the code, or add the fft_sink call
to my own .py (preferred) and output to stdout.  Specifically, I need to
access the data from fft_sink to find the maximum, and output it's
frequency/value.  How do I do this?

FWIW, I'm using the gnuradio as a cheap spectrum analyzer.  If I can
ascii to stdout, I can make some RF measurements.

Any help with the gnuradio python interface would be appreciated.  I've
looked through the docs online, but the I/O with fft_sink isn't obvious
me. (a non-programmer who writes ugly c-code when absolutely necessary)


Abram Young                  Room:       PAS-259
Dept. of Physics             Voice:      520.621.4134
University of Arizona        E-mail:
Bb3ff9c86361ea921a64632a4c46e824?d=identicon&s=25 Trond Danielsen (Guest)
on 2007-06-13 19:15
(Received via mailing list)
2007/6/13, Abram Young <>:
> frequency/value.  How do I do this?
You can either use the gr.max_xx or gr.argmax_xi blocks that are
available in trunk to get the maximum value or the argument of the
maximum value from the FFT.

Or you can just sink the signal to a vector sink, and process the
recorded signal with numpy/scipy or octave/matlab if that is your cup
of tea.

Trond Danielsen
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