Cole impedance extractions from the step-response of a current excited fruit sample

Freeborn, Todd J.; Maundy, Brent; Elwakil, Ahmed S.

doi:10.1016/j.compag.2013.07.017

Cited by 52 publications

(20 citation statements)

References 34 publications

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“…The fractional order circuits can find practical use in precision measurement, or modelling of various biological signals [3,13,26]. Another use may be in electrical engineering [2][3][4][5][6][7][8][9][10][11][12][13][14][15]32], telecommunications [2] and also agriculture [16].…”

Section: Introductionmentioning

confidence: 99%

Fractional-order low-pass filter with electronic tunability of its order and pole frequency

Langhammer

Dvořák

Jeřábek

et al. 2018

Journal of Electrical Engineering

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This paper presents novel solution of a fractional-order low-pass filter (FLPF). The proposed filter operates in the current mode and it is designed using third-order inverse follow-the-leader feedback topology and operational transconductance amplifiers (OTAs), adjustable current amplifiers (ACAs), auxiliary multiple-output current follower (MO-CF) as simple active elements. The filter offers the beneficial ability of the electronic control of its order and also the pole frequency thanks to electronically controlled internal parameters of OTAs and ACAs. As an example, five particular values of fractional order of the FLPF were chosen and parameters of the filter were calculated. Similarly, also electronic control of the pole frequency of the filter was studied. The design correctness and proper function of the filter are supported by simulations with CMOS models and also by experimental laboratory measurements. Comparison of the simulation results of the proposed filter for two different approximations of the parameter s α is also included. K e y w o r d s: adjustable current amplifier; current mode; electronically tunable; fractional-order; FLPF; low-pass filter; operational transconductance amplifier

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Section: Introductionmentioning

confidence: 99%

Fractional-order low-pass filter with electronic tunability of its order and pole frequency

Langhammer

Dvořák

Jeřábek

et al. 2018

Journal of Electrical Engineering

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“…Few methods were previously discussed to extract the Cole-Cole impedance module (Cole and Cole, 1941), such as those in (Freeborn et al, 2013), (Maundy et al, 2015) and (Valente and Demosthenous, 2016). Meanwhile, there are hardly any portable low-cost impedance analyzers in the market that can be employed on a wide scale.…”

Section: Introductionmentioning

confidence: 99%

Design of a Portable Low-Cost Impedance Analyzer

Al-Ali

Elwakil

Ahmad

et al. 2017

Proceedings of the 10th International Joint Conference on Biomedical Engineering Systems and Technologies

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Impedance analyzers available in the market are mostly bulky and often very expensive. In this paper, a low-cost, portable impedance analyzer is designed and implemented. The design utilizes the well-known, impedance network analyzer chip AD5933 and is capable of measuring a spectrum of impedances in the range 5 Hz to 100 kHz from 10 Ω to 100 kΩ. Its specifications allow it to be used in agriculture for monitoring the bio-impedance of fruits in different stages of their lives, especially during the growth period while maintaining low-cost.

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“…The circuit parameters that represent the impedance of a biological tissue are typically determined using direct impedance measurements, which require both the magnitude and phase of the fruit or vegetable to be measured. However, previous works have investigated the extraction of these parameters without direct impedance measurements using only the magnitude response [20,21] or step response [22] to reduce the hardware complexity and determine the impedance by eliminating the requirement of measuring the phase response (for magnitude methods) or generating sinusoidal test signals (for time-domain methods). However, although these previous methods have verified the accuracy of using the magnitude response to extract the circuit parameters, [20,21] no studies have explored the variability of parameters extracted from the same fruit using different electrode positions.…”

Section: Introductionmentioning

confidence: 99%

Variability of Cole-model bioimpedance parameters using magnitude-only measurements of apples from a two-electrode configuration

Freeborn

Elwakil

Maundy

2017

International Journal of Food Properties

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Electrical impedance measurements have been widely researched to monitor physiological changes in fruits and vegetables in a nondestructive manner. Recently, the parameters of the Cole bioimpedance model (R 0 , R 1 , C, and α), an equivalent circuit that is widely used to represent the electrical impedance of biological tissues, were extracted using techniques without direct impedance measurements. In this study, the variability of the Cole parameters extracted from magnitude-only measurements (from 200 Hz to 1 MHz) of apples in a twoelectrode setup was examined to understand the impact of electrode placement on the parameters evaluated using this technique. Eight electrodes were placed around the center latitudinal line of apples to collect seven sets of measurements from four different varieties (Granny Smith, Fuji, Red Delicious, and Spartan). The Cole impedance parameters were extracted in MATLAB from the collected measurements using a nonlinear least squares fitting method. These extractions indicated that the parameters R 0 and R 1 had the highest variability based on the electrode location, whereas the dispersion coefficient (α) had the lowest variability.

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Cole impedance extractions from the step-response of a current excited fruit sample

Cited by 52 publications

References 34 publications

Fractional-order low-pass filter with electronic tunability of its order and pole frequency

Fractional-order low-pass filter with electronic tunability of its order and pole frequency

Design of a Portable Low-Cost Impedance Analyzer

Variability of Cole-model bioimpedance parameters using magnitude-only measurements of apples from a two-electrode configuration

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