Title :
Measurement of memory effects in predistortion linearizers
Author_Institution :
Eur. Space Agency, Noordwijk, Netherlands
Abstract :
Detrimental effects of memories in linearizers are described, and two efficient techniques are presented to measure them. These techniques allow a real-time adjustment and correction of the linearizer and/or amplifier circuits and an overall improvement of the intermodulation performance over a wide-envelope frequency band. The effects of memory are shown for a 20-W L-band power amplifier utilizing bipolar devices and linearized by means of a predistorting network. It is shown that predistortion linearization in the presence of strong memory effects becomes extremely complex if not impossible. The compensation of the amplifier nonlinearities (amplitude and phase) is significantly affected and limited by the time delay characteristics of the system.<>
Keywords :
compensation; electric distortion; intermodulation; microwave amplifiers; power amplifiers; solid-state microwave circuits; 20 W; L-band power amplifier; amplifier circuits; bipolar devices; compensation; intermodulation performance; memory effects; predistorting network; predistortion linearizers; real-time adjustment; time delay characteristics; wide-envelope frequency band; Circuits; Distortion measurement; Frequency measurement; Nonlinear distortion; Performance evaluation; Phase distortion; Phase measurement; Power amplifiers; Power measurement; Predistortion;
Conference_Titel :
Microwave Symposium Digest, 1989., IEEE MTT-S International
Conference_Location :
Long Beach, CA, USA
DOI :
10.1109/MWSYM.1989.38864
