Effect of HPA non-linearities on crosstalk and performance of digital radio systems

Author

Chen, Zhenguo ; Wang, Jing ; Feher, Kamilo

Author_Institution

Dept. of Electr. Eng. & Comput. Sci., California Univ., Davis, CA, USA

Volume

34

Issue

3

fYear

1988

fDate

9/1/1988 12:00:00 AM

Firstpage

336

Lastpage

343

Abstract

The performance of 64-QAM and 256-QAM systems amplified by nonlinear power amplifiers (HPAs) is investigated. Two types of HPAs are considered in the analysis. The quadrature crosstalk between the I and Q channels due to AM/AM and AM/PM conversion of the nonlinearities of the HPAs is studied by computer simulation and experimentally. The results reveal that the quadrature crosstalk is mainly caused by AM/PM conversion and that crosstalk is reduced when the output power backoff (OBO) is increased. However, for some HPAs, the crosstalk has the minimum in a certain range of OBO. The power spectra of intermodulation products caused by the nonlinearities of HPAs are shown. In addition, the probability of error performance, P(e), is computed for two types of HPAs and different OBO. A comparison of eye and constellation diagrams for TWTA operating at the different OBO is also given

Keywords

amplitude modulation; crosstalk; digital communication systems; digital simulation; power amplifiers; radio systems; 256-QAM systems; 64 QAM systems; AM/AM conversion; AM/PM conversion; I channel; Q channel; TWTA; computer simulation; crosstalk; digital radio systems; error performance probability; eye diagrams; high power amplifiers; intermodulation products; nonlinear power amplifiers; power spectra; quadrature crosstalk; Computer simulation; Crosstalk; Digital communication; FETs; Gallium arsenide; Nonlinear distortion; Phase distortion; Power amplifiers; Power generation; Quadrature amplitude modulation;

fLanguage

English

Journal_Title

Broadcasting, IEEE Transactions on

Publisher

ieee

ISSN

0018-9316

Type

jour

DOI

10.1109/11.7306

Filename

7306