Stability analysis of Cartesian feedback linearisation for amplifiers with weak nonlinearities

Author

Briffa, M.A. ; Faulkner, M.

Author_Institution

Victoria Univ. of Technol., Melbourne, Vic., Australia

Volume

143

Issue

4

fYear

1996

fDate

8/1/1996 12:00:00 AM

Firstpage

212

Lastpage

218

Abstract

RF amplifier linearisation by Cartesian feedback is analysed using a multiple input multiple output (MIMO) model. The effects of RF amplifier distortion, namely AM/AM and AM/PM distortion, are shown to degrade the stability of the Cartesian feedback loop. A versatile technique is presented that allows the amount of stability degradation to be determined for RF amplifiers provided distortion is not too large (i.e. class A to class AB amplifiers). Loops with low stability margins are shown to exhibit out-of-band noise peaking. It is concluded from the noise analysis undertaken, that the highest proportion of gain possible should be placed ahead of the loop compensation to minimise out-of-band noise

Keywords

MIMO systems; amplitude modulation; circuit noise; circuit stability; electric distortion; feedback amplifiers; linearisation techniques; pulse modulation; radiofrequency amplifiers; AM/AM distortion; AM/PM distortion; Cartesian feedback linearisation; MIMO model; RF amplifier distortion; RF amplifier linearisation; class A amplifiers; class AB amplifiers; feedback loop; gain; loop compensation; multiple input multiple output model; noise analysis; out-of-band noise minimization; out-of-band noise peaking; stability analysis; stability degradation; weak nonlinearities;

fLanguage

English

Journal_Title

Communications, IEE Proceedings-

Publisher

iet

ISSN

1350-2425

Type

jour

DOI

10.1049/ip-com:19960614

Filename

533170