By what means do you do step 5 - calling MCU calibration routine?
Step 5 is just title for steps 6…10. Maybe I’ve should used different notation.
Are all of gains in steps 6, 7, 8, 9, 10 all tx gains?
Yes, they are TX DC I, DC Q, Gain I, Gain Q and Phase.
If yes, than if I get it right, you search for a tx gain level which gives you best DC level.
Yes, just plain old binary-like search algorithm.
But how can I eliminate DC at the gain level that I need?
If you mean at different PAD gains, then you need to re-calibrate (or cache) calibration values for each PAD gain settings, as the offset drifts slightly with different PAD and fronteng gain settings.
What “other gains” do you mean in step 11? May be you meant other frequencies?
I meant that procedure 6…10 is repeated, but with respect to DC I, DC Q, Gain I, Gain Q and Phase.