Some authors proposed the extension of sigma-delta to implement filters, amplitude and phase modulators, correlators, adders, compandors, expanders, digital synthesizers, phase-locked loop etc. We believe that /spl Sigma//spl Delta/ should be seen as a novel domain for signal processing in parallel with continuous-time, sampled-data and digital. Interface blocks, operators available and the potential of the technique are discussed, and a wide set of applications like adder, multiplier, compandor, expander, AGC, synthesizers PLL, oscillators, filters are discussed. >

A software tool named TOSCA (Tool for Oversampled Switched-Capacitor A/D Converter Analysis) is described. The simulator is behavioral, general purpose and fully user-friendly. Because a set of basic building blocks is available, generic switched-capacitor noise-shaping A/D converters can be analyzed simply by building netlist file. Two hierarchical levels have been considered for circuit description: block level for subcircuits like quantizers and digital filters, and component level for subcircuits like the integrators where switches, capacitors and operational amplifiers are used as building elements. The developed models allow the most relevant nonideal parameters of the components to be taken into account, and a set of postprocessing facilities allows extensive analysis of the circuits. The program is written in C language, uses dynamic memory allocation, and is very fast.>