Multi-band look-up table type predistorter

摘要

A predistorter compensates, with high accuracy, for a distortion in each frequency band by a power amplifier that amplifies a transmission signal containing multiple frequency bands whose center frequencies are widely spaced apart. Signals of the respective frequency bands are extracted by multiple band signal extractors from the input signal containing transmission signals of multiple frequency bands; differences between the extracted signals and the output signal from the power amplifier are detected by multiple difference detectors in the respective bands; the detected difference signals are used as reference signals to read out compensation data from look-up tables for the respective frequency bands; the compensation data is added by multiple adders to the extracted transmission signals of the respective frequency bands; and the added outputs are combined by a combiner to provide the output signal from the predistorter.