This paper presents a new approach for estimating nonidealities in unit element feedback digital-to-analog converters (DACs) of sigma-delta analog-to-digital converters (SigmaDelta ADCs). The presented method involves a background correlation technique to determine static and dynamic device mismatches as well as a way to digitally correct a modulators output. Simulations show that the method can be used to precisely estimate imperfections and improve non-ideal modulators up to their ideal resolution. The method is defined mathematically and verified by simulations.