DIGITAL FILTERS FOR BAND-PASS SIGMA-DELTA CONVERTER FOR COMPLEX SENSOR SYSTEMS

Marián Chovanec, Linus Michaeli, Martin Sekerák, Ján Šaliga

Abstract

Sigma delta modulation is useful for high performance analog-to-digital conversion of narrow band signals. Band-pass sigma delta modulation (BP ΣΔ ADC) is suitable for communication systems such as AM/FM receivers and mobile phones. Application of BP ΣΔ ADC in sensor systems is presented in the paper. BP ΣΔ ADC performs I/Q conversion of the complex impedance from two dimensional sensor into two digital values representing real and imaginary part of sensor output. The BP ΣΔ ADC is useful for outputs processing from the modulating sensors too. Implemented digital filters have important impact on the metrological properties of whole BP ΣΔ ADC. The various types of FIR and IIR filters are studied in the paper and their phase sensitivity and transmission of modulated signal are studied.

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DOI

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IMEKO TC

TC4 - Measurement of Electrical Quantities

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