Roger A. Dalke, Robert J. Achatz , , , , and Yeh Lo

Abstract:

This report describes measurement, modeling, and simulation methods that are used to analyze the relationship between nonlinear operation of a typical PCS portable transceiver power amplifier and battery current, out-of-band power, and link margin. First the nonlinear characteristics of the PCS amplifier and associated battery current were obtained from amplifier measurements at various bias voltages and RF output signal levels. A mathematical model of the power amplifier based on these measurements was then used to simulate the communications link for purposes of determining the power spectral density and symbol-error ratio for a variable envelope digitally modulated signal using π/4 DQPSK with 35% root raised cosine filtering. The out-of-band power and symbol-error ratio were computed to determine the link margin for a maximum symbol-error ratio of 10-3.

Keywords: nonlinear amplifier; MMIC RF power amplifier; PCS transceiver amplifier; out-of-band

Disclaimer: Certain commercial equipment, components, and software may be identified in this report to specify adequately the technical aspects of the reported results. In no case does such identification imply recommendation or endorsement by the National Telecommunications and Information Administration, nor does it imply that the equipment or software identified is necessarily the best available for the particular application or uses.

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