Feedforward power amplifier control method using weight division adaptive algorithm

摘要

The weight division adaptive algorithm which is suitable to control a microwave FeedForward Power Amplifier (FFPA) is presented. In this algorithm, an output signal of a power amplifier is used as a reference signal to exclude the effect of the power amplifier to the convergence performances. The down converted complex reference signal is divided by the loop adjustment complex weight vector in the digital circuit. After the division, the phase difference between the reference signal and the error signals are calibrated, and then the Normalized Least Mean Square (NLMS) algorithm is applied. The proposed algorithm and the convergence condition are derived analytically. The effects of the proposed algorithm are verified by the nonlinear simulation of the FFPA using AM-AM and AM-PM nonlinearity of GaAsFET.