Gain/phase imbalance cancellation technique in LINC transmitters

A new technique for correcting the gain/phase imbalance in LINC transmitters is presented. The technique employs a feedback signal to generate an error signal, consisting mainly of intermodulation distortion. A direct search method is used to optimise the gain/phase imbalance for correction. An out-of-band radiation suppression of 10 dB was achieved using a signal processing workstation simulation package.