Recall from my previous announcements that addition of correction
registers and API for DC offset and IQ balance. Well, now you can use
special calibration utilities that come with UHD to improve RF
performance for WBX and SBX better than the out of the box specs.
So, I just merged these self-calibration utilities into the master
branch. These utilities can be used to minimize IQ imbalance and DC
offset through calibration adjustments. The calibration is automatic,
just run the utils, correction factors are saved and applied at runtime.
Currently, only SBX and WBX are supported. The utilities will not run on
USRP1, because it lacks the necessary FPGA fabric. More details and
instructions for how to use can be found here in the application notes:
If you plan on using the IQ balance calibration utility, I recommend
grabbing the latest images from here. Basically, these new images have
some tweaks to the dynamic range of the correction registers.