Multi-band lookup table type predistorter

A multi-band lookup table type predistorter for adding predistortion components for canceling distortion components produced by a power amplifier to an input transmitting signal and outputting the result comprising:

• N output side variable band signal extractors for extracting output signals in N frequency bands from output signals from the power amplifier, wherein N is an integer of 2 or greater;
• N difference detectors for detecting differences between transmitting signals in N frequency bands and N output signals from said N output side variable band signal extractors;
• N lookup tables for reading distortion compensation data of corresponding N frequency bands by using differences of said N frequency bands as reference signals;
• N adders for adding the distortion compensation data read out from said N lookup tables to the transmitting signals in the corresponding N frequency bands;
• a combiner for combining the added outputs from said N adders and outputting the combined result as a transmitting signal with the predistortion;
• and
• a frequency band controller for controlling frequency bands of said N output side variable band signal extractors.