Calculating transmitter power from spectral density I want to find out what is the real transmit power of my USRP 2922, unfortunately the only results I get when looking at the spectrum analyzer is the spectral power density.
These are the results of the my measurements (in LabView - transmitter parameters are: 1Mhz IQ Sampling rate, carrier: 2.4375GHz, 0 Tx gain, QPSK modulation; RX port on USRP receiver and TX port on USRP transmitter are connected with an attenuator):

Now, I'm wondering how to find the transmit power of the transmitter from this. The Gain control is for the RX Antenna gain, so it's not useful since it's not power of the USRP transmitter. Maybe I should integrate this value in the band? Alternatively for a sine of the signal, calculate the value from the amplitude? Any ideas?
You're right, to convert from a power density to a power, you integrate over frequency!
However:
Well, if neither of your transmitter nor receiver are calibrated, then you simply can't find the &quot;real&quot; transmitted or received power. The plots you have are &quot;amplitude relative to maximum ADC input&quot;. You don't know what power &quot;maximum ADC input&quot; corresponds to without calibration.
End of story - there's not a single absolute power in your system that you can use as reference!
The solution here is to calibrate; i.e. send a signal, measure it with a calibrated spectrum analyzer, measure the same signal with your USRP, and then calculate the factor between these two powers. Due to linearity, that factor (==corrective additive term in dB) stays the same for all powers.