Continuous Time Sigma-Delta Modulators
This chapter is dedicated to introducing the continuous time (CT) implementation of Sigma-Delta modulators. Therefore, the significant differences between discrete time and continuous time modulators will be analyzed, as well as the differences concerning the actual design process. On this regard, the mathematical equivalence between CT and DT modulators is presented and used to demonstrate the inherent anti-aliasing characteristic of CT designs. Moreover, important non-idealities which are specific to CT modulators, as well as some practical issues derived from actual circuits, will be discussed and suggestions for simulation practices of CT modulators in MATLAB/Simulink® provided. By the end of this chapter, the reader should have a basic knowledge of all the fundamentals relative to continuous time Sigma-Delta converters and be able to develop basic, high-level CT modulator systems in the Simulink® environment.
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