A tool for the fast distortion evaluation of non linear amplifiers in broadband transmission systems

A Simulink blockset for the fast evaluation of the non linear distortion caused by RF amplifiers, mixers and BaseBand amplifiers in broadband transmission systems such as the orthogonal frequency division multiplexing (OFDM) adopted in the WLAN or more recently in the UWB standard is presented. Each amplifier block within the tool is described by a ninth-order power series extracted from classical one-tone and two-tones parameters. The distortion description is directly deduced from the spectral analysis of the system, thus avoiding the need for time consuming, time domain simulations and providing a powerful tool for the fast evaluation of the design requirements. A Gaussian approximation is adopted to simplify calculations for high order distortion terms spectra. The blocks within the tool can be cascaded providing analytical predictions for the chain of two or more amplifiers as well. A simulation comparison to a time domain simulator proves that the model keeps reliable up to very high input power levels, outperforming former third-order and fifth-order power series approximations in the literature.