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Title: A Digital Interfacing Circuit Based on Sliding DFT Bins for Capacitive Sensors
Authors: Maurya O.P.
Sumathi, Parasuraman
Published in: IEEE Transactions on Instrumentation and Measurement
Abstract: A digital interfacing circuit (DIC) based on sliding discrete Fourier transform (SDFT) bins has been proposed for lossy capacitive sensors. The proposed interfacing circuit consisting of an analog sensing circuit and an analog-to-digital converter (ADC)-field-programmable gate array (FPGA)-based DIC. The sliding DFT bin-1 is employed as a quadrature signal generator to obtain in-phase and quadrature signals of the input supply voltage provided to the analog sensing circuit. The output sinusoidal signal of analog sensing circuit is correlated with the in-phase and quadrature signals separately and then averaged with SDFT bin-0 for computing sensing capacitance and resistance values. The proposed method is implemented in FPGA and tested for capacitance measurement range of 11 pF-5.27 nF with the maximum relative percentage error of 1.36%. The nonlinearity error is < 0.37% FS and FSS. Moreover, the suitability of the proposed interface for humidity measurement has been explored and validated experimentally with saturated salt solutions. Furthermore, the interdigitated capacitance is fabricated and tested with the proposed digital interface for the capacitance range of 30-122 pF, which finds an application in capacitive touchpad. © 1963-2012 IEEE.
Citation: IEEE Transactions on Instrumentation and Measurement, 70
Issue Date: 2021
Publisher: Institute of Electrical and Electronics Engineers Inc.
Keywords: Capacitive sensors
digital interfacing circuit (DIC)
field-programmable gate array (FPGA) implementation
sliding discrete Fourier transform (SDFT)
ISSN: 189456
Author Scopus IDs: 57218322336
Author Affiliations: Maurya, O.P., Department of Electrical Engineering, IIT Roorkee, Roorkee, India
Sumathi, P., Department of Electrical Engineering, IIT Roorkee, Roorkee, India
Corresponding Author: Sumathi, P.; Department of Electrical Engineering, India; email:
Appears in Collections:Journal Publications [EE]

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