Choosing Between Terminal and Independently Based Gain and Offset Error in the ADC Histogram Test

To recover the analog voltage at the input of an analog-to-digital converter (ADC) from its digital output, one needs to know at least the ADC gain and offset. For high-accuracy measurements, it is necessary to estimate the actual values of these parameters since they are usually different from the ideal values (one and zero, respectively). This estimation inevitably has an uncertainty, which contributes to the uncertainty of any measurement made with the ADC. Here, the precision of gain and offset error estimators, based on the histogram method for ADC testing is analyzed. The “terminal based” and “independently based” definitions are compared, both through simulation and experimental evaluation. Our conclusion is that, in typical conditions, the “independently based” definition is more precise.