Power-amplifier characterization using a two-tone measurement technique

Author

Clark, Christopher J. ; Silva, Christopher P. ; Moulthrop, Andrew A. ; Muha, Michael S.

Author_Institution

Multilink Technol. Corp., Santa Monica, CA, USA

Volume

50

Issue

6

fYear

2002

fDate

6/1/2002 12:00:00 AM

Firstpage

1590

Lastpage

1602

Abstract

An accurate nonlinear model is necessary to optimize the tradeoff between efficiency and linearity in power amplifiers. Gain compression (AM/AM) and amplitude-phase (AM/PM) distortion are the two primary model inputs used to characterize the nonlinearity. The amplifier´s AM/AM and AM/PM characteristics are typically measured statically using a vector network analyzer. Since the input is typically a modulated signal, it is desirable to characterize the amplifier dynamically. This paper describes and demonstrates a dynamic AM/AM and AM/PM measurement and modeling technique involving a spectrum analyzer and two-tone input signals. A complete analysis of the measurement technique is presented, along with the data processing needed for the identification of a new three-box model. The test configuration and procedure are presented with special precautions to minimize measurement error. Results for a solid-state amplifier are used to accurately predict intermodulation distortion, while those for a traveling-wave tube amplifier show good agreement with that obtained dynamically using a 16 quadrature-amplitude-modulation signal

Keywords

amplitude modulation; intermodulation distortion; measurement errors; microwave measurement; microwave power amplifiers; phase modulation; spectral analysers; travelling wave amplifiers; AM/AM characteristics; AM/PM characteristics; amplitude-phase distortion; data processing; gain compression; intermodulation distortion; measurement error; nonlinear model; power-amplifier characterization; primary model inputs; solid-state amplifier; spectrum analyzer; three-box model; traveling-wave tube amplifier; two-tone measurement technique; Data processing; Distortion measurement; Linearity; Measurement errors; Measurement techniques; Nonlinear distortion; Power amplifiers; Solid state circuits; Spectral analysis; Testing;

fLanguage

English

Journal_Title

Microwave Theory and Techniques, IEEE Transactions on

Publisher

ieee

ISSN

0018-9480

Type

jour

DOI

10.1109/TMTT.2002.1006421

Filename

1006421