DISTORTION COMPENSATION CIRCUIT

摘要

Provided is a distortion compensation circuit capable of improving performance of distortion compensation in an arbitrary frequency band. The present invention is a distortion compensation circuit which performs distortion compensation by digitally converting a feedback signal from an amplifier (3) using an ADC (5), passing the output from the ADC (5) through an FIR filter (12) having pass characteristics of a specific band which includes the used frequency band, outputting thereof to a quadrature demodulator (13), performing quadrature demodulation at the quadrature demodulator (13), computing LUT coefficients at an LUT coefficient computation unit (14), computing a value of an envelope at an envelope computation unit (15), reading the LUT coefficients corresponding to the value of the envelope from a lookup table at an LUT coefficient setting unit (16), outputting thereof to multipliers (17a and 17b), and multiplying the transmission signal by the LUT coefficients at the multipliers (17a and 17b).