[Discuss-gnuradio] Frequency shift in the received and generated signals of the USRP

[Bruhtesfa Ebrahim]

Hey all,

I am using USRP with two XCVR2450 Trancievers(working at 2.4-2.5GHz and 4.9-5.0GHz).
I generated a carrier at 2.45GHz from the USRP using :
 $ python usrp_siggen.py -TA -f2.45e9
But when i see the generated signal in a spectrum analyzer, i see that  it is shifted by 12.5KHz 
from the center frequency( i see the carrier at 2.45GHz minus 12.5KHz). I try for other carrier frequencies but the 
shift remain almost the same.

Also, I generated a carrierl of 2.45GHz from a signal generator , received  it in the usrp and I observed the spectrum. 
Again I see that the signal that is demodulated by the USRP and received in the computer through the USB is not a baseband signal as expected. Rather it is a carrier of about 12.5KHz.

This means their is a fequency shift of about 12.5KHz both in transmission and in reception.When I use a carrier of frequency 4.9-5.0GHz, the frequency shift almost doubles to 25KHz.
Does anyone experienced such a problem before?
So, What can i do to correct this frequency shift?   -Thanks


Bruhtesfa