[Legacy Report] Characterization of RF Power Amplifiers For Digital Pre-distortion Co-Sponsored by IEEE NNJ MTT/AP Chpater

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The distortion at the output of an RF power amplifier can conveniently be divided into two types. The first type,
which is independent of the bandwidth of the signal, arises from the curvature of the amplifier transfer function
(AM-AM and AM-PM) and it is quite easy to correct with digital pre-distortion. The second type, which is a
function of the bandwidth of the signal, becoming more prominent as the bandwidth increases, is the subject of
this presentation. Techniques to characterize this type of distortion are presented and it is shown that the data
leads to a simple model of the distortion which can be used as part of a digital pre-distortion algorithm to
correct the amplifier distortion. In addition to the attractive attribute of simplicity, this model is highly effective
in cancelling the amplifier distortion, it can be implemented at low cost, and it yields a rapid response time.
Dr. George Vella-Coleiro is a Senior Principal Engineer with Andrew LLC, a CommScope company, located
in Warren, NJ. He has worked on wireless communications systems for over 20 years, and on digital predistortion
algorithms and their implementation for over 10 years

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