Spectral sensitivity of predistortion linearizer architectures to filter ripple

Abstract

Multi-carrier power amplifiers (PA) used in cellular base stations have very high linearity requirement. Predistortion is a powerful method for linearization of RF PA. But linearity performance of a predistortion system is limited by various memory effects. We investigate the effects of filters between the predistorter and the PA. These effects are studied by means of analysis and simulation for multi-carrier signals. A method is developed that can be used to estimate the output spectrum based on the filter transfer function and the nonlinearity of the PA.