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.