Analog-to-digital conversion with piece-wise non-linear reference waveforms

摘要

A machine used for analog-to-digital (A/D) conversion in which an analog input is compared to a piece-wise non-linear analog reference waveform. A digital count is recorded indicative of when the difference between the two becomes zero. Alternative mappings such a linear correspondence between analog input values and digital output values can be implemented via digital processing of each recorded count. The invention is particularly intended for use with sinusoidal reference waveforms to enable low-cost, high-precision A/D conversion at speeds much higher than are possible with piece-wise linear analog reference waveforms such as saw-tooth or triangle waveforms. The invention can be implemented with multiple A/D converters sharing a piece-wise non-linear analog reference waveform, with conversion cycles using increasing or decreasing waveform segments, and with compensation of comparator-induced errors.