Spectrogram plot on ControlPort

GNU Radio
1

Does anybody know how to get gr-ctrlport-monitor to do spectrogram
plots? I set up a ctrlport_probe2_c block with the DISPSPEC DisplayType
but all I see are Time, PSD, and Constellation plot options in
gr-ctrlport-monitor.

Thanks,
Sean

2

On Thu, Aug 1, 2013 at 4:02 PM, Nowlan, Sean
[email protected] wrote:

Does anybody know how to get gr-ctrlport-monitor to do spectrogram plots? I
set up a ctrlport_probe2_c block with the DISPSPEC DisplayType but all I see
are Time, PSD, and Constellation plot options in gr-ctrlport-monitor.

Thanks,

Sean

I hadn’t actually enabled the spectrogram plots through our
ControlPort monitor app. It’s due to the way the data is handled that
makes it a slight pain to set up. It’s not impossible, but I just
hadn’t spent the time to do it. You can look in
gnuradio-runtime/python/gnuradio/ctrlport/GrDataPlotter.py and see
what you can do about adding it in.

I’ll likely get to it at some point, but not for the next few weeks at
least.

–
Tom
Visit us at GRCon13 Oct. 1 - 4
http://www.trondeau.com/grcon13

3

On Thu, Aug 1, 2013 at 4:02 PM, Nowlan, Sean [email protected] wrote:

Does anybody know how to get gr-ctrlport-monitor to do spectrogram
plots? I set up a ctrlport_probe2_c block with the DISPSPEC
DisplayType but all I see are Time, PSD, and Constellation plot options in
gr-ctrlport-monitor.

I hadn’t actually enabled the spectrogram plots through our ControlPort monitor
app. It’s due to the way the data is handled that makes it a slight pain to set
up. It’s not impossible, but I just hadn’t spent the time to do it. You can look
in gnuradio-runtime/python/gnuradio/ctrlport/GrDataPlotter.py and see what you can
do about adding it in.

I just copied the PSD functions and changed “Psd” to “Spectrogram” and
added waterfall sinks to get it working. However I had to remove a call
to “enable_autoscale(bool)” since that function isn’t a member of the
waterfall_sink_* classes. Does this sound like the right approach or do
I have to do something special to the data first?

–sean

4

On Tue, Aug 6, 2013 at 1:39 PM, Nowlan, Sean
[email protected] wrote:

–sean

That should definitely be a good start. You’re going to probably want
to have a rolling buffer that you fill up with the latest samples and
age off the oldest ones once its full. Otherwise, you’ll just get one
or two lines of the spectrogram plotted.

–
Tom
Visit us at GRCon13 Oct. 1 - 4
http://www.trondeau.com/grcon13

5

That should definitely be a good start. You’re going to probably want
to have a rolling buffer that you fill up with the latest samples and
age off the oldest ones once its full. Otherwise, you’ll just get one
or two lines of the spectrogram plotted.

I used the waterfall_sink_c class. Doesn’t that already buffer
everything it needs to display the plot? Are you talking about
additional buffering before the waterfall sink? It looks to be working
already.

–sean