Memory effect evaluation and predistortion of power amplifiers

This paper introduces the envelope model reference adaptive control construct to digital predistortion of RF power amplifiers. It is used to formulate a block level predistortion algorithm that compensates for the both memoryless compression characteristics and deterministic memory effects. An iterative technique of successive approximations is used to obtain the memory effect inverse function. The algorithm is applied to two amplifiers and convergence is demonstrated. Qualitative results (instantaneous input/output plots) and quantitative results (the sequence and ensemble RMS error over the iteration sequence) are presented.