Effectiveness of various dithering architectures for linearisation of high-resolution oversampling A/D converters

An essential disadvantage in application of the oversampling A/D converters in high-accuracy DC measurement instruments are local peaks of quantization errors observed for some specific input signal values. Those peaks, connected with appearance of the specific sequences of output signals, called "correlation codes", considerably lowers differential linearity and effective resolution of the converters for particular values of stationary input signals. Methods of reduction of those peaks of errors and linearization of sigma-delta converters transfer characteristics by means of non-subtractive and self-subtractive dither signals are described in the paper.