Sigma-delta modulation using filters with nonmonotonic transfer functions. Modelling and analysis

This paper presents sigma-delta modulation using filters with nonmonotonic transfer functions. Several computer-aided-design tools for the modelling and simulation of these sigma-delta modulator architectures, are presented. A tool developed using the MATLAB program is proposed. In the proposed tool, starting from an input netlist where the modulator topology and the non-idealities of the circuits to take into account are selected, a time-domain simulation is carried out at a behavioral level based on the functional description of the basic blocks. The results of the theoretical analysis and the facilities of the MATLAB program are used for modeling, analysis and performance evaluation of sigma-delta analog-to-digital converters. The results of simulation using MATLAB Toolboxes for Signal Processing, shows the following: the sigma-delta modulator with nonmonotonic filters have the advantage that their noise can be devoid of audio tones