| 摘要 |
It is intended to increase the efficiency of a distortion compensation amplification device having a pre-distorter 1. Level detecting means 11 detects a signal level, correspondence storage means 12 outputs a distortion compensation coefficient depending on the signal level, pre-distortion executing means 13 gives distortion with an inverse characteristic to the signal, filtering means 8 outputs a distortion component from a feedback signal output from an amplifier 4, and correspondence acquiring means 14 updates a learning coefficient constituting a function that gives the inverse characteristic so as to reduce the distortion component. The function that gives the inverse characteristic is expressed using a set of orthogonal polynomials. Each orthogonal function is the total sum of products of functions of the input signal and parameters, and the parameter values are set to cause the orthogonal functions to be orthogonal to each other when functions, which are obtained by applying a filter having the same characteristic as that of the filtering means 8 to the functions of the input signal, are replaced for the functions of the input signal constituting the orthogonal functions.
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