On Sat, Jul 21, 2012 at 12:44 AM, Thomas Tsou thomastsou@gmail.com wrote:
On Fri, Jul 20, 2012 at 6:09 PM, Alexander Chemeris alexander.chemeris@gmail.com wrote:
On Fri, Jul 20, 2012 at 10:22 PM, Thomas Tsou thomastsou@gmail.com wrote:
There are still other calibration issues, but phase noise is probably still a concern.
You mean LO leakage and I/Q balance? Have you calibrated them? They're very easy to do - I could guide you with Skype if needed.
LO leakage is calibrated. I/Q balance is not. Are there steps for this somewhere? I read 4.10 in the calibration guide, but I'm still not sure how to proceed.
I've started documenting this at the wiki: http://code.google.com/p/umtrx/wiki/LMS6002DCalibration#Tx_I/Q_balance_calib... Is that a good enough description for you?
Note, that FPGA registers which control I/Q imbalance compensation has been changed in the commit which introduced dual-channel Tx: https://github.com/chemeris/UHD-Fairwaves/commit/3d80d881d82e93ed39e83f72d5e... Host side hasn't been updated to accommodate those register changes yet. I would appreciate if you could do that.