On Measurement Uncertainty of ADC Nonlinearities in Oscillation-Based Test

Oscillation-based test (OBT) is one of the approaches for measuring static ADC parameters such as differential nonlinearity (DNL) and integral nonlinearity (INL) that can be implemented in a built-in self-test arrangement. When applying the OBT approach in practice we noticed an inherent measurement uncertainty related to the slope of the ADC input signal in OBT test mode. Experimental environment in Matlab has been set up to study the phenomenon. Experiments with varying values of slope were performed to demonstrate the margins of DNL measurement uncertainty.