| 摘要 |
A multi-band lookup table type pre-distorter is provided to reduce the number of additional devices due to a change of frequency bands and an increase of carrier waves by linearly amplifying frequency band corresponding to service conditions of wireless system. N output side variable band signal extractors(11-1,11-2) extract output signals of N frequency bands from output signals of a power amplifier and N is an integer of 2 or greater. N difference detectors(16-1,16-2) detect differences between transmitting signals in N frequency bands and N output signals from the N output side variable band signal extractors. N lookup tables(17-1,17-2) reads distortion compensation data of corresponding N frequency bands by using differences of the N frequency bands as reference signals. N adders(13-1,13-2) adds the distortion compensation data of the N lookup tables to the transmitting signals. A combiner(14) combines the added outputs of the N adders in order to output the combined result as a transmitting signal having predistortion. A frequency band controller(8) controls frequency bands of the N output side variable band signal extractors. |
