Member of: Analog (Because the Analog world has to be translated to the Digital world at some point)
General Operation
Nice summary of Sigma-Delta from [1]
"The structure of a typical first order Σ−∆ modulator is shown in Fig. 2. Charge from a reference leg and an input
leg are summed in an integrator. The integrator is inside a feedback loop, whose action is to control the polarity of the
reference charge so that the integrator output averages to zero. This occurs when the magnitude of the average
reference charge is equal over time to the input charge, i.e., when the charges are balanced. The reference charge is
derived by charging a known capacitor to a known (reference) voltage, but in a manner where the polarity can
be varied. In a conventional voltage input Σ−∆ converter, the unknown charge is derived from charging a fixed capacitor
to an unknown input voltage."
TODO: Draw a nice Σ−∆ modulator
Bibliography
[1] O'Dowd, J.; Callanan, A.; Banarie, G.; Company-Bosch, E., "Capacitive sensor interfacing using sigma-delta techniques," Sensors, 2005 IEEE , vol., no.pp. 4 pp.-, 30 Oct.-3 Nov. 2005
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