I misread you question and thought you were receiving with the USRP. Same procedure, just don't let the transmitted signal go past +/- 1.0 or you will clip the DAC. In practice keep it backed off 6 dB or more to allow for crest factor.
Lou madengr wrote > 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-tp55210p55220.html Sent from the GnuRadio mailing list archive at Nabble.com. _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio