how to tune the IQ imbalance

[neo]

if i want to tune the IQ imbalance, specially the quadrature imbalance, could you tell me some simple methods? i found it difficult for me, i mean, the analog approach, not digitally!

 

[rfsystem]

Ahhggg

Hot topic in analog IP. Search for IQ calibration on the free patent servers. The methods there are some years old but give you good introduction to the problems.

 

[neo]

we r all talking about the IQ imbalance (90°), what about the 180 phase imbalance, considering about the differential signal. if the diff-signal is 180°±10° or more before the down-mixer, does it harm to the demodulation or not?

 

[rfsystem]

Yes the impact is LO leakage in RX goes up. But for a divider for IQ generation phase gets imbalanced.