Embedded Wideband Measurement System for Fast Impedance Spectroscopy Using Undersampling

Munjal, Rohan; Wendler, Frank; Kanoun, Olfa

doi:10.1109/tim.2019.2932177

Cited by 25 publications

(12 citation statements)

References 27 publications

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“…From the table, one can see that this device performs favourably in terms of the magnitude and phase accuracy as well as the frequency bandwidth. The accuracy of the device is noteworthy as the ADC is only 10 bit while the most accurate device by Munjal et al [ 15 ] uses a 12 bit ADC. The cost is also competitive when the device cost outside of South Africa is considered.…”

Section: Resultsmentioning

confidence: 99%

“…In many of these applications, low-cost design is critical to the in situ use of impedance spectroscopy as a measuring technique. For this reason, low-cost impedance devices are of interest to the general sensors community, and there was significant development in the field of low-cost impedance spectroscopy devices [ 13 , 14 , 15 ], including our prior work on a low-cost system [ 16 , 17 ] for use in point-of-need applications. The conference paper [ 16 ] explored an EIS analytical technique by measuring concentrations of different salts in water for a potential multiplexed detection application.…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, the purpose of the current paper is the performance validation of the complete custom EIS device against an established commercial system implementation of EIS, as well as an illustrative evaluation of the custom implementation in an application-based testing environment. Instead of validating the device with artificial models assembled with passive components, as is often reported [ 15 , 18 ], it was decided to validate the performance of the low-cost device doing an experiment with water spiked with an analyte of interest in our ongoing water quality monitoring work [ 19 , 20 , 21 ].…”

Section: Introductionmentioning

confidence: 99%

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Validation of Low-Cost Impedance Analyzer via Nitrate Detection

Beer

Joubert

2021

Sensors

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Impedance spectroscopy is a widely used electrochemical technique with a wide variety of applications. Many of these applications benefit from the additional accessibility provided by low-cost impedance devices. With this in mind, a low-cost impedance device was designed for a high performance-to-cost ratio. The performance of this analyzer was validated against a high-performance DropSens µStat-i 400s potentiostat by performing an application-based experiment. Nitrate detection provides a relevant experiment because of the importance of maintaining precise nitrate concentrations to mitigate the impact of nitrate fluctuations on the environment. Dissolved nitrate samples of different concentrations, in the range 3–1000 mg/L, were confirmed colorimetrically and measured with both instruments. A calibration curve of the real impedance matched a sigmoidal transfer, with a linear region for concentrations below 10 mg/L. The device under investigation exhibited an average magnitude error of 1.28% and an average phase error of 0.96∘ relative to the high-performance standard, which validates the performance of the low-cost device. A cost analysis is presented that highlights some of the complexities of cost comparisons.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Validation of Low-Cost Impedance Analyzer via Nitrate Detection

Beer

Joubert

2021

Sensors

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“…microcontrollers [219], but most commonly, the Fourier transform is used, e.g. using undersampling [220]. Another approach is based on the Groetzel filter [221]- [223].…”

Section: ) Other Digital Approachesmentioning

confidence: 99%

Bioimpedance Sensors: A Tutorial

Kassanos

2021

IEEE Sensors J.

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Electrical bioimpedance entails the measurement of the electrical properties of tissues as a function of frequency. It is thus a spectroscopic technique. It has been applied in a plethora of biomedical applications for diagnostic and monitoring purposes. In this tutorial, the basics of electrical bioimpedance sensor design will be discussed. The electrode/electrolyte interface is thoroughly described, as well as methods for its modelling with equivalent circuits and computational tools. The design optimization and modelling of bipolar and tetrapolar bioimpedance sensors is presented in detail, based on the sensitivity theorem. Analytical and numerical modelling approaches for electric field simulations based on conformal mapping, point electrode approximations and the finite element method (FEM) are also elaborated. Finally, current trends on bioimpedance sensors are discussed followed by an overview of instrumentation methods for bioimpedance measurements, covering aspects of voltage signal excitations, current sources, voltage measurement front-end topologies and methods for computing the electrical impedance.

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“…On the other hand, a second technique has been investigated based on I-U measurements and fast Fourier transform (FFT) for impedance calculation. Munjal et al [ 13 ] propose a solution with an extended frequency range until 10 MHz using the under-sampling technique and achieves a maximal standard deviation of 0.5% and 0.55° deviation in amplitude and phase relatively. Based on the same technique, Vergas et al designed a portable system for detecting abnormalities in the gastrointestinal tract in the range from 10 Hz to 1 MHz with an accuracy of 2% [ 14 ].…”

Section: Introductionmentioning

confidence: 99%

Comparative Study of Measurement Methods for Embedded Bioimpedance Spectroscopy Systems

Atitallah

Kallel

Bouchaala

et al. 2022

Sensors

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Bioimpedance spectroscopy (BIS) is an advanced measurement method for providing information on impedance changes at several frequencies by injecting a low current into a device under test and analyzing the response voltage. Several methods have been elaborated for BIS measurement, calculating impedance with a gain phase detector (GPD), IQ demodulation, and fast Fourier transform (FFT). Although the measurement method has a big influence on the measurement system performance, a systematical comparative study has not been performed yet. In this paper, we compare them based on simulations and experimental studies. To maintain similar conditions in the implementation of all methods, we use the same signal generator followed by a voltage-controlled current source (VCCS) as a signal generator. For performance analysis, three DUTs have been designed to imitate the typical behavior of biological tissues. A laboratory impedance analyzer is used as a reference. The comparison addresses magnitude measurement accuracy, phase measurement accuracy, signal processing, hardware complexity, and power consumption. The result shows that the FFT-based system excels with high accuracy for amplitude and phase measurement while providing the lowest hardware complexity, and power consumption, but it needs a much higher software complexity.

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Embedded Wideband Measurement System for Fast Impedance Spectroscopy Using Undersampling

Cited by 25 publications

References 27 publications

Validation of Low-Cost Impedance Analyzer via Nitrate Detection

Validation of Low-Cost Impedance Analyzer via Nitrate Detection

Bioimpedance Sensors: A Tutorial

Comparative Study of Measurement Methods for Embedded Bioimpedance Spectroscopy Systems

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