Adaptive digital correction of gain and phase imbalances in LINC transmitters

The linear amplification using nonlinear components (LINC) technique is a well-known power amplifier linearization method to reduce adjacent channel interference in a nonconstant envelope modulation system. Its major drawback is the inherited sensitivity to gain and phase imbalances between the two amplifier branches. In this paper, a novel adaptive full-digital base band method is described which corrects any gain and phase imbalances in LINC transmitters. Its main advantage is the ability to track the input signal variations and adapt to the changes of amplifier nonlinear characteristics.