Title :
A novel predistorter using a balanced type IM3 generator
Author :
Sang Won Kim ; Hyeong Tae Jeong ; Chul Dong Kim ; Ik Soo Chang
Author_Institution :
Dept. of Electron. Eng., Sogang Univ., Seoul, South Korea
Abstract :
This paper presents a novel linearization scheme for a nonlinear RF amplifier. It is based on amplitude modulation with the envelope signal. The 3/sup rd/ order distortion generator is composed of two FETs and it adopts a balanced structure for the purpose of main carrier cancellation. The amplitude and phase of the IM3 components can be controlled in the RF band. This predistorter is implemented and tested at the KOREA PCS Tx band (1840/spl sim/1870 MHz). Experimental results of the two-tone test show that the IM3 cancellation of about 30-40 dB is achieved for a wide dynamic range. The adjacent channel power ratio is improved by over 10 dB for the CDMA signal with a peak to average power ratio of 10 dB, and this improvement is maintained over a wide range of output power levels.
Keywords :
UHF power amplifiers; amplitude modulation; circuit testing; code division multiple access; field effect transistor circuits; harmonic distortion; intermodulation distortion; linearisation techniques; 1840 to 1870 MHz; CDMA signal peak to average power ratio; FET circuits; IM3 component amplitude/phase control; PCS Tx band; adjacent channel power ratio; balanced main carrier cancellation structures; balanced type IM3 generators; envelope signal amplitude modulation; intermodulation distortion; nonlinear RF amplifier linearization schemes; output power level range; predistorters; third-order distortion generators; two-tone tests; wide dynamic range IM3 cancellation; Amplitude modulation; Dynamic range; FETs; Multiaccess communication; Nonlinear distortion; Peak to average power ratio; Personal communication networks; Radio frequency; Radiofrequency amplifiers; Testing;
Conference_Titel :
Microwave Symposium Digest, 2003 IEEE MTT-S International
Conference_Location :
Philadelphia, PA, USA
Print_ISBN :
0-7803-7695-1
DOI :
10.1109/MWSYM.2003.1210947
