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On the Implicit Anti-Aliasing Feature of Continuous-Time Cascaded Sigma–Delta Modulators

2007; Institute of Electrical and Electronics Engineers; Volume: 54; Issue: 12 Linguagem: Inglês

10.1109/tcsi.2007.906070

1558-0806

Matthias Keller, Alexander Buhmann, Friedel Gerfers, Maurits Ortmanns, Yiannos Manoli,

CCD and CMOS Imaging Sensors

This paper deals with one of the most outstanding advantages of continuous-time (CT) sigma-delta modulators compared to their discrete-time counterparts: the implicit anti-aliasing feature (AAF). Although inherent in any CT architecture, analysis of anti-aliasing properties has mostly been restricted to single-stage modulators in the past. In this contribution, extensions on analysis methods for the study of the AAF of CT multistage noise-shaping architectures are covered. A theoretical model is introduced and confirmed through simulation results. Contrary to previous belief, the results indicate that usually all stages of a cascaded architecture are involved in the anti-aliasing behaviour and hence that it is not solely determined by the first stage.