Different measurement methods for characterizing and detecting memory effects in non-linear RF power amplifiers

Memory effects exhibited in RF power amplifiers (PA) have been identified as a major source of performance degradation in modern digital communication systems. While advanced amplifier linearization schemes, such as a digital predistortion (DPD) and envelope elimination restoration, are being used to improve efficiency and linearity in modern digital communication systems, they can also expose communication networks to unwanted emissions from memory effects if not carefully designed and tested. This paper gives a brief description of origins of memory effects in RF power amplifiers. Available methods to quantify memory effects caused by such as parasitic elements are reviewed. Finally a new method based on digital phosphor display technology (DPX) on Real Time Spectrum Analyzers for detecting the presence the memory effects is introduced and its unique capabilities to perform time-correlated measurement results are presented.