On the synthesis and optimization of cascaded continuous-time Sigma-Delta modulators

[摘要] Up to now, there exist two completely different approaches for thesynthesis of cascaded CT Sigma-Delta modulators. While the firstmethod is based on a DT prototype and thus on the application of aDT-to-CT transformation, the second one is entirely performed in theCT domain. In this contribution, the method of lifting will beapplied to overcome the disadvantages afflicted with the firstmethod (e.g. less ideal anti-aliasing filter performance, increasedcircuit complexity) and to establish a time efficient DT simulationmodel for the second method. Thereby, optimal modulator coefficientsas well as optimal digital cancellation filters for an arbitrarycascaded CT modulator can be simulated in an efficient and rapidmanner. For illustrative purposes, the complete synthesis procedureis demonstrated by the example of a 2-1-1 cascaded CT modulator.

[学科分类] 电子、光学、磁材料