scholarly journals Development of an electrical impedance based spirometer

2018 ◽  
Vol 9 (1) ◽  
pp. 17-27
Author(s):  
Md Anas Ali ◽  
M Abdul Kadir ◽  
K Siddique e Rabbani
Keyword(s):  
Measurement System ◽  
Electrical Impedance ◽  
Medical Physics ◽  
Impedance Measurement ◽  
Current Drive ◽  
The Body ◽  
Constant Current ◽  
Forced Expiration ◽  
Voltage Measurement ◽  
Asthma Patients

Spirometry, or measurement of respiration conventionally involves measurement of the time variation of volume or flow of air breathed in or out through the mouth using an air-flow sensor. Electrical impedance of thorax changes during breathing and conceptually this modality should be applicable in spirometry, but no attempts have been made so far. This paper describes the development of an electrical impedance based spirometer placing electrodes on four limbs so that the whole lung volume may contribute to the measurement. An impedance based measurement system (IBS) consisting of a constant current drive at 11 kHz and necessary voltage measurement circuitry was designed and developed for this purpose. A portable oscilloscope (PicoScope 2208A) was used for acquisition of the measured voltage signal to a PC and an algorithm in Matlab software was used to demodulate the time varying impedance from a carrier signal. The variation of impedance with time during forced expiration as measured by the implemented impedance measurement system was compared with that obtained using a standard bellows type commercial spirometer (Vitalograph) on eight volunteers, between 22 and 32 years of age. The subjects included smokers, non-smokers, and asthma patients. Repeatability of the measurements were satisfactory. The correlation coefficient between the spirogram obtained using the IBS and that obtained using standard spirometer varied from 0.81 to 0.99 indicating preliminary success of the proposed technique. However, a possible source of error is the bending of the body during forced expiration which, if prevented, may give a better outcome.Bangladesh Journal of Medical Physics Vol.9 No.1 2016 17-27

scholarly journals Design of a Microcontroller Based System to Implement 4-Electode Focused Impedance Method (FIM)

2013 ◽  
Vol 4 (1) ◽  
pp. 75-79
Author(s):  
Dr Aktharuzzaman ◽  
Tanvir N Baig ◽  
K Siddique-e Rabbani
Keyword(s):  
Measurement System ◽  
Medical Physics ◽  
Impedance Measurement ◽  
Simulation Software ◽  
Signal Generator ◽  
Constant Current ◽  
Impedance Method ◽  
Electronic Circuitry ◽  
Measuring Unit

Designing of electronic circuitry and development of necessary software has been performed in the present work for a microcontroller based 4-electrode Focused Impedance measurement system. This needs a complex sequential analog switching of constant current ac signal generator and a potential measuring unit to 4 electrodes on the object under study. The performances of the designed system and the developed microcontroller software have been studied using a commercially available simulation software, ‘Proteus-7’, and the results are very satisfactory. DOI: http://dx.doi.org/10.3329/bjmp.v4i1.14690 Bangladesh Journal of Medical Physics Vol.4 No.1 2011 75-79

Measurement of loudspeaker mechanical impedance by changing the sound load at the throat of loudspeaker

2021 ◽  
Vol 263 (1) ◽  
pp. 5457-5466
Author(s):  
Shichun Huang ◽  
Liang Yu ◽  
Weikang Jiang
Keyword(s):  
Measurement System ◽  
Electrical Impedance ◽  
Structural Parameters ◽  
Impedance Measurement ◽  
Mechanical Impedance ◽  
Coupling Model ◽  
Acoustic Energy ◽  
Mathematical Relationship ◽  
Radiation Impedance ◽  
Acoustic Coupling

A loudspeaker is a device that converts electrical energy into acoustic energy by coupling between electrical impedance, mechanical impedance, and radiation impedance. The loudspeaker electro-mechanical-acoustic coupling model provides the experimental feasibility to measure the characteristic parameters. In this paper, an economical and practical measurement method of loudspeaker mechanical impedance is proposed. First, the mathematical relationship between loudspeaker electrical impedance and mechanical impedance is obtained based on the loudspeaker electro-mechanical-acoustic coupling model. Second, two electrical impedances with different known radiation impedance are measured by using a developed measurement system. Finally, the real and imaginary parts of the mechanical impedance are obtained according to the mathematical relationship. This method neither assumes that the loudspeaker mechanical impedance is constant in a frequency band nor does it build FEM models based on structural parameters. A loudspeaker is measured by using a developed measurement system. The result shows that the mechanical impedance and the force factor are functions of frequency. Moreover, a radiation impedance measurement is performed to verify the feasibility and accuracy of the proposed method.

A Design Based on Bioimpedance Spectroscopy Method in Human Abdominal Adipose Measurement System

2012 ◽  
Vol 263-266 ◽  
pp. 241-245 ◽  
Author(s):  
Zhang Yong Li ◽  
Fei Ba Chang ◽  
Xiao Bo Chen ◽  
Rui Leng ◽  
Wei Wang
Keyword(s):  
Measurement System ◽  
Current Source ◽  
Impedance Measurement ◽  
Bioelectrical Impedance ◽  
Abdominal Fat ◽  
Signal Generator ◽  
Constant Current ◽  
Phase Detection ◽  
Bioimpedance Spectroscopy ◽  
Constant Current Source

This article describes a measurement of human abdominal fat device designed based on BIS (bioimpedance spectroscopy), the device adopts four electrodes multi-frequency bioelectrical impedance measurement system, including the programmable signal generator module and the amplitude and phase detection module. Program controlled signal generator module can generate the high output impedance of the constant current source in the eight frequency points constant current source between 5KHz and1MHz; amplitude phase detecting module can detect the human body electrical impedance real part and imaginary part information. Therefore, the device can be accurate measurement of human abdominal impedance information in the whole frequency range. Meanwhile, according to the selected electrode fixed position and the appropriate measurement scheme, can calculate the corresponding depth of abdominal fat content.

scholarly journals Probing for stomach using the Focused Impedance Method (FIM)

2019 ◽  
Vol 10 (1) ◽  
pp. 73-82
Author(s):  
Rashida Haque ◽  
Muhammad Abdul Kadir ◽  
K Siddique-e Rabbani
Keyword(s):  
Low Income ◽  
Electrical Impedance ◽  
Impedance Measurement ◽  
The Body ◽  
Low Income Countries ◽  
Impedance Method ◽  
Impedance Tomography ◽  
Cross Sectional ◽  
Sensitivity Equations ◽  
Element Simulation

Abstract For probing deep organs of the body using electrical impedance, the conventional method is to use Electrical Impedance Tomography (EIT). However, this would be a sophisticated machine and will be very expensive when a full 3D EIT is developed in the future. Furthermore, for most low income countries such expensive devices may not deliver the benefits to a large number of people. Therefore, this paper suggests the use of simpler techniques like Tetrapolar Impedance Measurement (TPIM) or Focused Impedance Method (FIM) in probing deeper organs. Following a method suggested earlier by one of the authors, this paper studies the possibility of using TPIM and FIM for the stomach. Using a simplified model of the human trunk with an embedded stomach, a finite element simulation package, COMSOL, was used to obtain transfer impedance values and percentage contribution of the stomach region in the total impedance. For this work, judicious placement of electrodes through qualitative visualizations based on point sensitivity equations and equipotential concepts were made, which showed that reasonable contribution of the stomach region is possible through the use of TPIM and FIM. The contributions were a little over 20% which is of similar order of the cross-sectional area percentage of the stomach with respect to that of the trunk. For the case where the conductivity of the stomach region was assumed about 4 times higher, the contributions increased to about 38%. Through further studies this proposed methods may contribute greatly in the study of deeper organs of the body.

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