Re: [Discuss-gnuradio] GRC, Recording chunks of spectrum triggered on input signal level

[madengr]

If you are using an "if" statement to switch between filename and /dev/null,
try putting the filename construction in the "if" statement, instead of a
separate variable.  That may make it evaluate every time the "if" statement
is called.

My example used the LO frequency as part of the filename, and every time the
QT GUI slider changed the LO, it probably updated the filename.

If that does not work, maybe you can use a probe to examine a signal, say
10x a second.  Then the probe level() function could be used as part of the
filename.  That would at least change it 10x a second.

For the counter, maybe you could also use a probes to look at a signal
before and after a N sample delay, where delay and sample rate is about the
same time as your probe rate; then this pseudocode:

if now.level() != delayed.level() then count = count +1

At this point though you ought to delve into the Python.  As long as you are
not using the QT GUI, the code is pretty straight forward.  You can use
probes to pull values out of the flow and evaluate them in Python.

Thanks,
Lou
KD4HSO
 
  


Staffan wrote
> Hello,
> 
> After some weekend experimenting I believe I have most (most...) of it 
> working. Sinking to a USB stick is not working so well by the way...
> One thing that is still a challenge is how to set the filename. You
> provided 
> a very good way of timestamping, but when I try this, it only evaluates 
> once - when I start the script. Is there any way to force re-evaluation of
> a 
> variable?
> In addition, it would be great to have some kind of a counter (variable, x
> = 
> x + 1) that can be updated depending on a state change - for example when
> a 
> trigger event occurrs. I tried some different versions, but mainly ended
> up 
> in circular references...
> 
> Any suggestions would be highly appreciated!
> 
> Regards,
>   Staffan





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