A Coefficient Optimization and Architecture Selection Tool for ΣΔ Modulators in MATLAB

A tool created in MATLAB environment for automatic transfer function generation and topology synthesis for a sigma delta modulator for a desired frequency response is proposed in this work. The tool carries out two basic tasks: (1) transfer function generation, which works in a SPICE like fashion, taking the netlist of an arbitrary SD modulator architecture in block level as the input, determining the input-output relation for each block in z-domain and generating the signal and noise transfer functions (STF and NTF) of the system automatically, (2) a topology synthesis algorithm which uses the STF and NTF as inputs and finds all the possible SD modulator topologies (according to some criteria such as minimization of the number of signal paths) which can be obtained from the architecture and which realizes a desired frequency response. The application of the tool will be illustrated on examples