Digital Equalizer Design of Biosensor for Portable Bioimpedance Analyzer

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DOI: https://doi.org/10.20998/2522-9052.2020.2.15
Keywords:
portable bioimpedance analyzer, biosensor, auto-balancing circuit, digital equalizer, dynamic errors correction algorithm

Main Article Content

Yuriy Khoma
National University "Lviv Polytechnic", Lviv
https://orcid.org/0000-0002-4677-5392
Volodymyr Khoma
National University "Lviv Polytechnic", Lviv
https://orcid.org/0000-0001-9391-6525

Abstract

The article describes a new design approach for portable bioimpedance analyzers. The novelty of this approach is based on the idea to synthesize the correction algorithms that perform as a digital equalizer to equalize the frequency response of the bioimpedance sensor. The implementation of the approach allows expanding the operating frequency range for more than two orders without increasing the complexity of the structure of the bioimpedance measuring channel. The subject of the study is a method of design a low-cost bioimpedance analyzer for personal use, in particular as a wearable device. The purpose of the study is to develop a new design for a biosensor as a basic component of a portable bioimpedance analyzer. The approach is based on the maximum simplification of the analog part of the biosensor and the use of computational tools to correct the dynamic errors of the measuring channel. A key aspect of the implementation of this approach is the synthesis of the digital equalizer function as a set of algorithms for dynamic errors correction. Results. The expediency of bioimpedance sensor design by the method of auto-balancing bridge balancing has been proven in the paper. Dynamic errors that limit the operating frequency range are shown to be the main problem along the way. The transfer function of the auto-balancing circuit is analyzed and the three most significant sources of dynamic errors are identified. The transfer function is formalized, where the error sources are represented by three coefficients. The methodology of the synthesis of the correction algorithms for "raw" measurement results, which essentially realize the function of the digital equalizer, is proposed. It is stressed that the implementation of the digital equalizer does not require any additional changes in the structure of the bioimpedance sensor, as it only requires the computational resources that are already available as a part of the modern measuring instrumentation. The efficiency of the correction algorithms in the frequency range from 10 Hz to several MHz is investigated by modeling the bioimpedance sensor in the Pspice simulation software. Research results have shown the possibility of extending the operating frequency range by more than two frequency orders. Conclusions. The necessity of developing a digital equalizer for a portable bioimpedance analyzer is shown in the article. An innovative approach is proposed to reduce dynamic errors based on synthesis and use of correction algorithms. The efficiency of the synthesized algorithms is investigated and the possibility of significant expansion of the operation frequency range of portable bioimpedance analyzer is demonstrated.

Article Details

How to Cite
Khoma, Y., & Khoma, V. (2020). Digital Equalizer Design of Biosensor for Portable Bioimpedance Analyzer. Advanced Information Systems, 4(2), 100–109. https://doi.org/10.20998/2522-9052.2020.2.15
Issue
Vol. 4 No. 2 (2020): Advanced Information Systems
Section
Methods of information systems synthesis
Author Biographies

Yuriy Khoma, National University "Lviv Polytechnic", Lviv

Candidate of Technical Sciences, Asistant Professor of Information and Measurement Technology Department

Volodymyr Khoma, National University "Lviv Polytechnic", Lviv

Doctor of Technical Sciences, Professor, Professor of Information Security Department

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