Digital predistorter for 64QAM modulation based on FPGA device

This paper presents a predistortion technique compensating for nonlinear distortions caused by HPA (High Power Amplifier) in an QAM (Multilevel Quadrature Modulation) system. Investigations were held both with software and hardware tools. It is confirmed by computer simulation that proposed approach produces a faster convergence speed than traditional computer performed algorithms. Predistortion technique based on programmable logic device is a very attractive from the implementation point of view, because of a low amount of required RAM and rapid convergence from a blind start.