Adaptive baseband digital predistorter suitable for wideband signals

In this paper, we present a new topology for an adaptive baseband digital predistorter suitable for wideband signals. The proposed predistorter is composed of a cascade of a fixed LUT based predistorter and an adaptive linear subband filter´s bank. The linear subband filters serve to compensate for the dependency of the RF power amplifier behavior on the temperature. In this work, measured AM/AM and AM/PM characteristics of an LDMOS class A/B amplifier were used for the predistorter performances evaluation purposes. The simulation results using a CDMA2000 signal show a good performance in terms of the out of band emission reduction of the amplifier output spectrum.