Forum: GNU Radio How does probe level works

C428a98c19238bab0c875dbc0ef91214?d=identicon&s=25 dilip thapa (Guest)
on 2013-08-19 07:08
(Received via mailing list)
Hi,

I am trying to detect the presence of primary user by energy detection.
And after searching I was advised to use probe block to do the sense.
(gr.probe_avg_mag_sqrd_f).

Can anyone explain how this works. How level() method gives the energy
level.

~Dilip
C2ed5433862330f8d76de8eb807851ca?d=identicon&s=25 Mike Jameson (Guest)
on 2013-08-19 10:44
(Received via mailing list)
Hi Dilip,

Have a look at the scanoo GRC flowgraph build in GNU Radio 3.7 which
uses
the probe functions for spectrum sensing:

https://github.com/m0mik/scanoo

This is the GRC flowgraph in question:

https://raw.github.com/m0mik/scanoo/master/apps/sc...

The 'Function Probe' block is used to call either the 'level()' or
'unmuted()' function in the probe_avg_mag_sqrd block.  You can then
access
the value using the name of the 'Function Probe' block.  The same
technique
applies for calling the value of the 'Probe Signal' and 'Probe Signal
Vector' blocks, however these only have the 'level()' function
available.

Regards,

Mike

--
Mike Jameson M0MIK BSc MIET
Email: mike@scanoo.com
Web: http://scanoo.com
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