Digital adaptable Pre-Distortion Linearization

This paper describes an adaptive digital RF predistorter using lookup table (LUT), phase shift and attenuator modules. The LUT are deduced from the behaviour of input and output signals of the high power amplifier (HPA). The measured intermodulation product of a linearized SSPA reveals a significant improvement despite the non monotonic behaviour of the HPA nonlinearities. The experimental evaluation is carried out using an RF digital predistorter prototype that mainly includes an envelop detector, phase shift and attenuator modules, field programmable gate array for the LUT and fast analog/digital and digital/analog converters.