Behavior Modeling of the Amplifier Nonlinearity With the AC Josephson Voltage Standard

Behavior models of electronic components are critical in many metrological and measurement areas, e.g., time-domain simulations for analog-integrated circuit design and predistortion of the amplifier to reduce the distortion. This paper describes the use of pulse-driven ac Josephson voltage standard (ACJVS) to synthesize quantum accurate waveforms with ultralow distortion and noise floor to model the amplifier nonlinearity, which is a promising way to increase the modeling accuracy. Four Volterra series models including the memory polynomial model and three submodels of the dynamic deviation reduction model are analyzed and compared in detail. Normalized mean square error is calculated to evaluate the modeling accuracy. The difference of the measured and predicted outputs of the amplifier are compared in both time and frequency domains. The result shows that high-performance models can be achieved, which demonstrates the feasibility of modeling nonlinear amplifier behavior with the ACJVS.

I. Introduction

Ideally, the behavior of an amplifier should be linear. However, memory and distortion effects degrade its performance and result in nonlinear features. Mathematical modeling of amplifier behavior with models has received increased attention, especially in two areas. First, when using computer aided design (CAD) tools to conduct system level analyses, the behavior models are required and the simulation accuracy depends strongly on the performance of the models [1]. Behavior modeling of the analog amplifier converts the amplifier from analog domain to digital domain, and thus enables digital-domain simulations. Second, in many applications, predistortion of the amplifier with its inverse model is one of the key techniques for reducing nonlinear distortion [2]–[4].