A/D converter having digitally controlled subranging and self-alignment apparatus for use therein

摘要

A subranging analog-to-digital converter is disclosed having digitally controlled subranging for eliminating switching gain and switching paths in the analog section thereof. The digitally controlled subranging apparatus may be applied to either a single time-shared quantizer embodiment or a converter embodiment including a plurality of simultaneously operated quantizers. In either case, the conversion is formed in a series of quantizer operations on a sampled analog signal input for forming a final accumulated digital word conversion representative thereof. Another aspect of the present invention includes the addition of apparatus in a subranging A/D converter for maintaining the pre-alignment of the various conversion dynamic subranges thereof. In this aspect, the subranges of the converter are prealigned to affect a unique set of digital conversion codes of subranged conversions of the analog signal input value corresponding to the conversion threshold transition regions between the pre-aligned subranges. An anomaly in the digital conversion codes of said analog signal input value is detected and used to govern the adjustment of the conversion dynamic range of at least one of the quantizers of the converter in order to ameliorate the anomalous condition.