Reducing quantization noise with recursive ΣΔ modulators

This paper introduces a recursive multibit ΣΔ architecture that enables a high effective quantizer resolution while needing only a limited number of DAC elements. The recursive architecture consists of a set of ΣΔ modulators, whereby each stage cancels the quantization noise of the proceeding stage. Conventional DEM algorithms can be used in each stage to reduce the sensitivity to mismatch. The architecture enables a significant reduction of both the signal-band and out-of-band quantization noise power, compared to conventional multibit ΣΔ converters.