Abstract: An analog-to-digital conversion system uses a fast analog-to-digital converter having a resolution less than the system resolution to convert the difference between a previously predicted value and the current analog value. The converted difference is summed with the predicted value to compute the actual value of the analog input signal to a resolution greater than that of the fast analog-to-digital converter. The high resolution digital value thus obtained becomes the predicted value for the next conversion. This predicted value is converted by a digital-to-analog converter having the same accuracy but not the same resolution as the system output to an analog signal which is compared with the input analog signal to obtain a difference signal. This difference signal is sampled and held to provide the input to the fast analog-to-digital converter.