A digital predistorter for power amplifier with memory effect

When a conventional predistorter compensating the nonlinear distortion in a power amplifier is used, the compensation characteristics deteriorate as the signal bandwidth is increased, to such a degree that the memory effect is no longer negligible. In this paper, it is shown experimentally that the memory effect is caused by fluctuations of the input voltage at low frequency. Measured data are introduced into the simulation. A predistorter that can deal with the memory effect is presented. It is shown by simulation and experiments that the distortion compensation characteristic can be improved. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 89(12): 20–30, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20314