DIRECT INTERPOLATION METHOD FOR REDUCING THE NONLINEARITY AND QUANTIZATION DISTORTION OF ANALOG-TO-DIGITAL CONVERTERS

A direct interpolation method is described that reduces the distortion due to quantisation and linearity errors of practical analogue-to-dig ital convertors. In contrast with other interpolation systems, the ana logue signal is not oversampled, and no feedback loops are required. C ompared with the conventional use of 'dither', direct interpolation pr ovides an increase in signal-to-noise ratio as well as a reduction in harmonic distortion. Computer simulations and experimental measurement s are presented. The method is particularly suited,to reducing high-or der harmonics and increasing the effective resolution of an ADC.