Analysis and elimination of hysteresis and noisy precursors in power amplifiers
Abstract
Power amplifiers (PAs) often exhibit instabilities leading to frequency division by two or oscillations at incommensurate frequencies. This undesired behavior can be detected through a large-signal stability analysis of the solution. However, other commonly observed phenomena are still difficult to predict and eliminate. In this paper, the anomalous behavior observed in a Class-E PA is analyzed in detail. It involves hysteresis in the power-transfer curve, oscillation, and noisy precursors. The precursors are pronounced bumps in the power spectrum due to noise amplification under a small stability margin. The correction of the amplifier performance has required the development of a new technique for the elimination of the hysteresis. Instead of a trial-and-error procedure, this technique, of general application to circuit design, makes use of bifurcation concepts to suppress the hysteresis phenomenon through a single simulation on harmonic-balance software. Another objective has been the investigation of the circuit characteristics that make the noisy precursors observable in practical circuits and a technique has been derived for their elimination from the amplifier output spectrum. All the different techniques have been experimentally validated.
Additional Information
© Copyright 2006 IEEE. Reprinted with permission. Manuscript received June 20, 2005; revised October 14, 2005. [Posted online: 2006-03-06] This work was supported by the Lee Center for Advanced Networking, California Institute of Technology and by Qualcomm. The authors would like to thank C. Wheatley, Qualcomm, San Diego, CA, for support. The authors would also like to thank J.-M. Collantes, University of the Basque Country, Bilbao, Spain, for helpful comments.Files
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Additional details
- Eprint ID
- 5520
- Resolver ID
- CaltechAUTHORS:JEOieeetmtt06a
- Created
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2006-10-20Created from EPrint's datestamp field
- Updated
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2021-11-08Created from EPrint's last_modified field