A Design of the Predistorter Using Same Structure of the IMD Generators

In this paper, we propose the new linearization scheme for nonlinear RF power amplifier, generating the third and fifth intermodulation distortion signals it uses the identical structure of intermodulation signal generator. The proposed predistorter generates and controls predistorted third and high order IM signals independently. Using predistorted signals, intermodulation distortion signals of power amplifier are suppressed effectively. The predistortion linearizer has been implemented to operate in Korean PCS base-station transmitting band(1840~1870 MHz). The test results show that IM3 and IM5 (C/I) of power amplifier are improved more than 45 dB and 30 dB for CW two tone signals, respectively. The predistorter improves the adjacent channel power ratio (ACPR) more than lOdB at 885 kHz offset point for CDMA (IS-95) signals.