Automatic calibration of quadrature balance in cartesian loop amplifier

This report describes the method for adaptively pre-distorting the drive signal to the Cartesian amplifier to reduce the level of quadrature imbalance. The procedure involves a calibration procedure implemented on a Digital Signal Processor (DSP) that is either carried out periodically during transmission or prior to each transmission depending on the total transmit time. Recommendations for the choice of Cartesian loop amplifier parameters are wesented as a result of the analysis.