Analog Realization of Fractional-Order Skin-Electrode Model for Tetrapolar Bio-Impedance Measurements

Alimisis, Vassilis; Dimas, Christos; Pappas, Georgios; Sotiriadis, Paul P.

doi:10.3390/technologies8040061

Cited by 22 publications

(12 citation statements)

References 60 publications

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“…The electrode's surface area seems to be an important factor, since smaller surfaces lead to higher contact impedances. The contact impedance effect is more intense at lower frequencies [59,60]. Mismatches between the channels' contact impedances may lead to common signals, especially at the voltage recording circuitry part.…”

Section: Simulation Resultsmentioning

confidence: 99%

Evaluation of Thoracic Equivalent Multiport Circuits Using an Electrical Impedance Tomography Hardware Simulation Interface

et al. 2021

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Electrical impedance tomography is a low-cost, safe, and high temporal resolution medical imaging modality which finds extensive application in real-time thoracic impedance imaging. Thoracic impedance changes can reveal important information about the physiological condition of patients’ lungs. In this way, electrical impedance tomography can be a valuable tool for monitoring patients. However, this technique is very sensitive to measurement noise or possible minor signal errors, coming from either the hardware, the electrodes, or even particular biological signals. Thus, the design of a good performance electrical impedance tomography hardware setup which properly interacts with the tissue examined is both an essential and a challenging concept. In this paper, we adopt an extensive simulation approach, which combines the system’s analogue and digital hardware, along with equivalent circuits of 3D finite element models that represent thoracic cavities. Each thoracic finite element model is created in MATLAB based on existing CT images, while the tissues’ conductivity and permittivity values for a selected frequency are acquired from a database using Python. The model is transferred to a multiport RLC network, embedded in the system’s hardware which is simulated at LT SPICE. The voltage output data are transferred to MATLAB where the electrical impedance tomography signal sampling and digital processing is also simulated. Finally, image reconstructions are performed in MATLAB, using the EIDORS library tool and considering the signal noise levels and different electrode and signal sampling configurations (ADC bits, sampling frequency, number of taps).

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Section: Simulation Resultsmentioning

confidence: 99%

Evaluation of Thoracic Equivalent Multiport Circuits Using an Electrical Impedance Tomography Hardware Simulation Interface

et al. 2021

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“…Another method for bioimpedance measurements was described in [ 70 ] and was simulated in 90 nm CMOS technology. The presented method is based on the fractional-order capacitor emulator that is shown in Figure 27 .…”

Section: Biomedical Applications From the Measurement Perspectivementioning

confidence: 99%

Amplifiers in Biomedical Engineering: A Review from Application Perspectives

Kouhalvandi

Matekovits

Peter

2023

Sensors

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Continuous monitoring and treatment of various diseases with biomedical technologies and wearable electronics has become significantly important. The healthcare area is an important, evolving field that, among other things, requires electronic and micro-electromechanical technologies. Designed circuits and smart devices can lead to reduced hospitalization time and hospitals equipped with high-quality equipment. Some of these devices can also be implanted inside the body. Recently, various implanted electronic devices for monitoring and diagnosing diseases have been presented. These instruments require communication links through wireless technologies. In the transmitters of these devices, power amplifiers are the most important components and their performance plays important roles. This paper is devoted to collecting and providing a comprehensive review on the various designed implanted amplifiers for advanced biomedical applications. The reported amplifiers vary with respect to the class/type of amplifier, implemented CMOS technology, frequency band, output power, and the overall efficiency of the designs. The purpose of the authors is to provide a general view of the available solutions, and any researcher can obtain suitable circuit designs that can be selected for their problem by reading this survey.

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“…In general, the desired tunability in the Gaussian function curve's variance is achieved by connecting a control voltage to the Body node of some of the differential block's transistors. By incorporating a differential difference pair [5,6,17,18,24,[52][53][54] an increased linearity [56], along with additional output currents are provided. In either case, the control voltage provides sigmoidal shaped curves I 1 , I 2 with adjustable slopes or symmetric displacement of currents.…”

Section: Bulk-controlled Implementationsmentioning

confidence: 99%

Analog Gaussian Function Circuit: Architectures, Operating Principles and Applications

et al. 2021

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This review paper explores existing architectures, operating principles, performance metrics and applications of analog Gaussian function circuits. Architectures based on the translinear principle, the bulk-controlled approach, the floating gate approach, the use of multiple differential pairs, compositions of different fundamental blocks and others are considered. Applications involving analog implementations of Machine Learning algorithms, neuromorphic circuits, smart sensor systems and fuzzy/neuro-fuzzy systems are discussed, focusing on the role of the Gaussian function circuit. Finally, a general discussion and concluding remarks are provided.

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Analog Realization of Fractional-Order Skin-Electrode Model for Tetrapolar Bio-Impedance Measurements

Cited by 22 publications

References 60 publications

Evaluation of Thoracic Equivalent Multiport Circuits Using an Electrical Impedance Tomography Hardware Simulation Interface

Evaluation of Thoracic Equivalent Multiport Circuits Using an Electrical Impedance Tomography Hardware Simulation Interface

Amplifiers in Biomedical Engineering: A Review from Application Perspectives

Analog Gaussian Function Circuit: Architectures, Operating Principles and Applications

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