Re: [Discuss-gnuradio] Measuring the Level of a Peak in a Signal

[Marcus Müller]

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Hi George,

practical implementation aside: Thanks to Parseval's theorem, looking
at relative signal strength in frequency and time domain is equivalent.
You can just use a number sink or time sink with a low pass filter to
visualize the received signal power of the carrier. If you're feeling
like doing things completely right, you can automatically fine tune to
the carrier by using PLL carrier tracking ;)

As for implementation: there is the max block. What you could do is:
PLL -> low pass -> complex to mag² -> integrate -> stream to vector ->
max/argmax (depends on what you actually want to do)
but that will not "update" your maximum during runtime but only find
the maximum within a vector.

However, implementing an "always output the (abs)maximum float value"
block is really easy as a python block - in fact, doing that might be
a great start into developing GNU Radio blocks. Doing it somewhat
optimized might need some thought, though ;)

Greetings,
Marcus

PS: please make sure not to respond to previous posts when bringing up
a new topic; otherwise, your post will appear in that thread and is
more likely to be ignored.

On 20.03.2014 16:05, George S. Williams wrote:
> I imagine this is doable, but between experimenting and Google I
> have not been able to find a solution. The application is fairly
> simple- a FCD is connected to a QT GUI Sink. The FCD is tuned to
> the pilot frequency of a ATSC television channel. The attached
> image shows the resulting spectrum. The application is intended to
> assist in pointing an antenna to receive television broadcasts in a
> rural area.
> 
> What I would like to do is measure the peak and display a number
> that represents its level. I have been able to average the entire
> signal but can't figure out how to measure the peak. Any advice
> would be appreciated.
> 
> Thanks, George
> 
> 
> 
> _______________________________________________ Discuss-gnuradio
> mailing list address@hidden 
> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
> 
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