Using Recursive Multibit Sigma-Delta Modulators to Reduce the Quantization Noise Power

This paper discusses a recursive multibit Σ∆ 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 Σ∆ modulators, whereby each stage cancels the quantization noise of the preceding 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-ofband quantization noise power, compared to conventional multibit Σ∆ converters.