An analog to digital converter (ADC) system includes two signal paths in parallel with each other, where the signal paths include separate ADC circuits to separately operate on a same input signal and output separate digital signals. A difference signal is calculated as a difference of the digital signals output from the two signal paths to determine an error present in one or both of the signal paths. The error may be modulated in one or both of the signal paths and demodulated from the difference signal according to a same digital modulation pattern to compute an error compensation signal to compensate for at least one of the modulated error and a secondary error resulting from the modulation of the error.