US Patent 7994856 Predistorter, predistortion method, and predistortion system

This invention relates to a predistorter, a predistortion method, and a predistortion system. The predistorter comprises a modulus value determining section, for determining a modulus value of an input signal; a base searching section, for searching a predetermined base lookup table in accordance with the modulus value of the input signal, so as to obtain a base lookup table value; an offset searching section, for searching a predetermined offset lookup table in accordance with the modulus value of the input signal, so as to obtain an offset lookup table value; an interpolation factor generating section, for generating an interpolation factor in accordance with the modulus value of the input signal; a multiplying section, for multiplying the offset lookup table value with the interpolation factor; and a summating section, for adding a product obtained by the multiplying section to the base lookup table value, so as to obtain a predistortion value.