I am trying to create a complex cosine signal in 100kHz and transmit it
with USRP in 110MHz using WBX daughterboard. I have observed this signal
in an oscilloscope and a spectrum analyzer. It can be seen that there is
a nonexistent peak at transmit frequency of USRP. I also added the
related photos to be clear.
Any help would be kindly appreciated.
You are most likely seeing the local oscillator at the centre due to the
WBX being a direct conversion daughterboard:
To remove this, you can put the following in the center frequency box of
the UHD source/sink block in GRC:
The ‘uhd_center_freq’ and ‘uhd_lo_offset’ need to be specified. Set
‘uhd_lo_offset’ to be something like ((samp_rate/2)*1.1).
Mike J. M0MIK BSc MIET
Ettus R. Technical Support
Email: [email protected]
Web: http://www.ettus.com http://www.ettus.com
Also, please be sure you run the calibrations provided by UHD. The TX DC
Offset calibration addresses exactly what you are talking about.