[Discuss-gnuradio] RFX 2400 daughter board: emission

[sylvain poulenard]

USRP emission problem:
 
I do not understand the FFT of my spectrum analyzer connected to an USRP that emitted a cosine signal source at 10kHz through a USRP sink centred on 2.464GHz (see figure emission_calibration.png )
Indeed, I got three peaks at:
f =2.464 GHz
f =2.468 GHz
f =2,472 GHz
Moreover the power emitted should be typically around 50mW, 17dBm, but I catch -43dBm after a cable of loss = 1,6dB

If I receive on another USRP, the result of the FFT on the computer is on figure "FTT_result_USRP_source.png"
The FTT on the computer seems to be right, even if I do not catch the order of magnitude of the FFT ordonnee.
To sum up, I have three questions:
- Why three peaks on the spectrum analyser?
- Power emitted?
- What is the scale of the FTT ordonne?
I am stuck, so thank you very much for your help

FTT_result_through USRP_source.png
Description: PNG image

emission_calibration.png
Description: PNG image