Power Amplifier Linearisation Through Generation and Injection of Low-Frequency Second-Order Nonlinear Products

This paper reports on a novel linearisation technique that is applicable to high power amplifiers used with digitally modulated single- or multi-carrier signals. The analysis, simulations and measured results demonstrate that improvements in distortion (ACPR, ACLR and EVM) can be achieved with a relatively small increase in signal processing overhead and minimal hardware complexity. This paper presents the underlying concept by applying frequency-domain analysis to an amplifier modelled by a truncated power series. The technique has been successfully applied to EDGE and QPSK-modulated carrier signals, and both simulation and measured results are presented.