Re: [Discuss-gnuradio] duration of uhd_rx_cfile script

[Marcus D. Leech]

On 14/12/11 03:21 AM, Sebastian Döring wrote:
> Hello all,
>
> I just measured the time the execution of uhd_rx_cfile.py takes all
> together.
> I used N=20000, samp-rate=1M and the rest was left to the default values.
>
> In theory the taking of the samples should take T=N/B=20ms but I had
> to discover that the whole process is taking about 2s.
>
> Does anybody know what exactly is taking so long and if there is a way
> to speed it up?
> Since I am actually planning to somehow use this script (or parts of
> it) in the context of spectrum sensing/monitoring for dynamic access,
> 2 seconds is definitely taking to long.
>
>
> Thanks in advance.
>
> Sebastian
>
> _______________________________________________
>
Well, there's loading the Python interpreter, and the shared libraries
it immediately relies on.  Then
  there's loading all of the gnuradio and other "stuff" that is
"imported" into your running Python image.
  Then there's creating and starting the flow-graph.  Then there's the
setting-up of the hardware that
  UHD has to do on startup.  Yup, I can see that taking 2 seconds or more.

If what you want to do is "set frequency, record some data for awhile,
change to a new frequency,
  rinse, repeat", then you're better off writing a custom flow-graph
that does that, rather than trying
  to "script" something like uhd_rx_file.py.  Once a flow-graph is setup
and created, the overhead drops
  quite a bit.

I think: gnuradio/gr-uhd/examples/usrp_spectrum_sense.py

Already does a lot of what you want.




-- 
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org