Non Linear Distortions introduced by Amplifiers on COFDM signals. Measurements, Effects and Compensation Techniques

Abstract

Coded Orthogonal Frequency Division Multiplexed (COFDM) techniques, used by terrestrial European broadcasting systems (DAB, DVB-T), could be adopted in the last mile of the downlink channel for Wireless Broadband Communication System to provide Multimedia Services to mobile or nomadic users by cellular coverage techniques, as evinced from the actual research activity. COFDM signals are characterised by non-constant envelope (peak-to-mean power ratio > 10 dB) which forces to project amplifiers with low or well-counteracted nonlinear distortion effects. Our aim is to present Itelco experience to characterise non-linear distortions introduced by final amplifiers on COFDM signals (AM/AM, AM/PM and NonLinearities with Memory