A 5th-order analog predistorter for NADC system

• Published in: 2010 IEEE International Conference on Communication Systems pp. 19 - 22
• Main Authors: Sun, X L, Cheung, S W, Yuk, T I
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01-11-2010
• Subjects: Attenuators; Generators; Power generation; Predistortion; Resistors; Signal generators
• ISBN: 1424470048; 9781424470044
• DOI: 10.1109/ICCS.2010.5686111

This paper presents the design of a 5 th -order analog predistorter using the inband intermodulation (IM) signals for predistortion of base-station high power amplifiers (HPAs) for the North American Digital Cellular (NADC) system. The predistorter employs two mixers with same configuration to generate 3 rd -order intermodulation (IM3) products and 5 th -order intermodulation (IM5) products, to suppress the 3 rd -and 5 th -order intermodulation distortion products (IMDP3 and IMDP5) at the HPA output. The predistorter is implemented and tested using the pi/4-DQPSK signal of the NADC system at 2.2GHz in a practical 100W-HPA. The results show that, at the HPA output powers of 65.6, 56.2, 50 and 41.3 W, the predistorter can suppress the adjacent channel power ratio (ACPR) of the pi/4-DQPSK signal at ± 20 kHz from the center frequency by 15.16, 15.83, 16.17 and 15.17 dB, respectively.