1) Send in a CW tone from a signal generator of known power (dBm) 2) Read the level from GR FFT (dB) 3) Figure out the amount you need to offset (dB) 4) Multiply your samples by a constant value of 10**(offset_dB/20.0) 5) The GR FFT will now be calibrated to an absolute power (dBm).
Note if you change any settings, technically you would have to go through this again. Lou Jan wrote > Hi guys, > > I transmitted this -30 dB signal (Image 1) using a usrp: The spectrum > analyzer displays -50 dBm (Image 2) as its reading. My receiver end picked > up the signal with the same peak power at -30 dB (Image 3). I'm confused. > How > do I convert the dB power in the GRC to the received signal of the > spectrum > analyzer in dBm? How do I convert the Power (dB) of the FFT to dBW or dBm? > > Best, > > *Gerome Jan M. Llames * -- View this message in context: http://gnuradio.4.n7.nabble.com/GRC-FFT-Plot-tp55210p55217.html Sent from the GnuRadio mailing list archive at Nabble.com. _______________________________________________ Discuss-gnuradio mailing list [email protected] https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
