Re: [Discuss-gnuradio] Some usrp_spectrum_sense.py code Explanation

[Ling Huang]

Interrupting Output Spectrum
-----------------------------

The actual mapping from the levels at the daughterboard antenna input port
to the output analysis values depends on a lot of factors including the used
daughterboard RF gain and decimation specific gain in the digital down
converter. You'll need to calibrate the system if you need something that
maps to dBm.Currently, the output of usrp_spectrum_sense is the magnitude
squared of the FFT output.  That is, for each FFT bin[i], the output is Y[i]
= re[X[i]]*re[X[i]] + im[X[i]]*im[X[i]]. If you want power, take the square
root of the output. 

========================================================================================
Hi, Firas
In my opinion the ouput Y[i] has the same dimension with the power. If we
square root the output, and divide it with the fft bin numbers, then we get
the voltage magnitude.
Am I right? 

Best Regards,
Ling


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