Patent ID: 7561636

Claim:
A digital predistortion apparatus for compensating by predistorting a nonlinear characteristic caused by a power amplifier that amplifies an input signal, the apparatus comprising: a predistorter, electrically connected to the power amplifier via a digital-to-analog converter (DAC), for receiving the input signal and compensating for the nonlinear characteristic using a look-up table that depends upon a change in output power of the power amplifier; and a look-up table (LUT) updating block, electrically connected to the predistorter, for comparing a feed-back signal outputted from the power amplifier with a first signal outputted from the predistorter, and adaptively updating the look-up table using the compared result, wherein the LUT updating block comprises: a delay unit for calculating a time delay between the first signal and the feed-back signal, delaying the first signal by the calculated time delay, and providing the delayed first signal to an adaptation controller; the adaptation controller for updating a polynomial coefficient converged to reduce a difference between an output value and a target value; and an LUT converter for converting the polynomial coefficient converged in the adaptation controller into a look-up table to update the look-up table.