A novel signal-predicting multibit delta-sigma modulator

In this paper, the signal-predicting oversampling scheme (Lu et al. (2002)) is developed for the design of the internal quantizers of multibit delta-sigma (ΔΣ) modulators. By applying the scheme, it has been derived that, regardless of the resolution of the internal quantizer, only 4 comparators are required in a first-order multibit ΔΣ modulator provided that an appropriate oversampling ratio (OSR) is chosen. To verify the derived results, an illustrative signal-predicting first-order 4-bit ΔΣ modulator with 4 comparators is presented. Simulation results show that the modulator functions very well and when compared with a corresponding modulator with a normal flash internal quantizer, in which 16 comparators have to be used, the proposed modulator demonstrates advantages in power consumption and silicon area.