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Alexander Chemeris alexander.chemeris at gmail.comOn Sat, Jul 21, 2012 at 7:03 AM, Thomas Tsou <thomastsou at gmail.com> wrote: > I tried calibrating LO leakage cancellation again and found out that > it wasn't calibrated enough. The settings are very sensitive and > increasing the I and Q shifts by one made a large difference on the > E4406. This is my experience as well. Near the optimum point even change of calibration registers by 1 makes big difference. When you're far off, a change of a calibration register could be almost unnoticeable. I've started adding notes about LMS calibration here: http://code.google.com/p/umtrx/wiki/LMS6002DCalibration Please write down there all useful notes about all types of calibration we're doing. > The RSA seems to compensate, though, because the same changes > don't affect it at all. How could it compensate? For RSA it should look like a genuine sine signal. > I also tried some different frequencies. At the not useful frequency > of 240 MHz, we are not far from target values. At 945 MHz, it is > better than before, but still too high. The 1900 MHz band is not so > good. Well, we're more interested in GSM900, but this clearly shows that there is an issue with the LMS PLL noise. -- Regards, Alexander Chemeris. CEO, Fairwaves LLC / ООО УмРадио http://fairwaves.ru