New methods for adaptation of quadrature modulators and demodulators in amplifier linearization circuits

Author

Cavers, James K.

Author_Institution

Sch. of Eng. Sci., Simon Fraser Univ., Burnaby, BC, Canada

Volume

46

Issue

3

fYear

1997

fDate

8/1/1997 12:00:00 AM

Firstpage

707

Lastpage

716

Abstract

Imperfections in analog quadrature modulators (QMs) and demodulators-gain and phase imbalance and DC offset-have a devastating effect on amplifier linearization circuits. Correction circuits have a simple structure, but their parameters must be adjusted adaptively. This paper introduces two new methods for such an adaptation. The first is based on a training sequence consisting of a tone at one or more amplitudes, and the second needs no training sequence at all. They are faster and more robust than previously published methods

Keywords

amplifiers; demodulation; demodulators; land mobile radio; linearisation techniques; modulation; modulators; radiofrequency amplifiers; DC offset; adaptation methods; amplifier linearization circuits; analog quadrature demodulators; analog quadrature modulators; circuit parameters; correction circuits; gain imbalance; mobile radio; phase imbalance; tone amplitudes; training sequence; Adaptive systems; Circuits; Convergence; Demodulation; Land mobile radio equipment; Phase modulation; Predistortion; Quantization; Robustness; Testing;

fLanguage

English

Journal_Title

Vehicular Technology, IEEE Transactions on

Publisher

ieee

ISSN

0018-9545

Type

jour

DOI

10.1109/25.618196

Filename

618196