Measurement of Static ADC Nonlinearities Using the Servoloop Method

When in-circuit static testing of analog-to-digital converters (ADCs) is needed, a low overhead in terms of hardware and data processing is a requirement. The servoloop is a feedback-based test method, common in industrial environments, that satisfies both needs. It is described in this paper, and its features are analyzed. A mathematical model based on a Markov chain is used to characterize its metrological performance. Simulation and experimental data that validate the developed theory are shown. Finally, a reproducible test procedure to obtain a given measurement uncertainty is presented