An Approach to Evaluate Electromagnetic Interference with a Wearable ECG at Frequencies below 1MHz

Wei LIAO; Jingjing SHI; Jianqing WANG

doi:10.1587/transcom.E98.B.1606

An Approach to Evaluate Electromagnetic Interference with a Wearable ECG at Frequencies below 1MHz

Wei LIAO, Jingjing SHI, Jianqing WANG

Full Text Views

0

Share
Cite this

Summary :

In this study, we propose a two-step approach to evaluate electromagnetic interference (EMI) with a wearable vital signal sensor. The two-step approach combines a quasi-static electromagnetic (EM) field analysis and an electric circuit analysis, and is applied to the EMI evaluation at frequencies below 1 MHz for our developed wearable electrocardiogram (ECG) to demonstrate its usefulness. The quasi-static EM field analysis gives the common mode voltage coupled from the incident EM field at the ECG sensing electrodes, and the electric circuit analysis quantifies a differential mode voltage at the differential amplifier output of the ECG detection circuit. The differential mode voltage has been shown to come from a conversion from the common mode voltage due to an imbalance between the contact impedances of the two sensing electrodes. When the contact impedance is resistive, the induced differential mode voltage increases with frequency up to 100kHz, and keeps constant after 100kHz, i.e., exhibits a high pass filter characteristic. While when the contact impedance is capacitive, the differential mode voltage exhibits a band pass filter characteristic with the maximum at frequency of around 150kHz. The differential voltage may achieve nearly 1V at the differential amplifier output for an imbalance of 30% under 10V/m plane-wave incident electric field, and completely mask the ECG signal. It is essential to reduce the imbalance as much as possible so as to prevent a significant interference voltage in the amplified ECG signal.

Publication: IEICE TRANSACTIONS on Communications Vol.E98-B No.8 pp.1606-1613

Publication Date: 2015/08/01

Publicized

Online ISSN: 1745-1345

DOI: 10.1587/transcom.E98.B.1606

Type of Manuscript: PAPER

Category: Electromagnetic Compatibility(EMC)

Authors

Wei LIAO
  Nagoya Institute of Technology
Jingjing SHI
  Nagoya Institute of Technology
Jianqing WANG
  Nagoya Institute of Technology

Keyword

electromagnetic interference (EMI), wearable electrocardiogram (ECG), sensing electrode, common mode voltage, differential mode voltage, quasi-static approximation

Cite this

Copy

Wei LIAO, Jingjing SHI, Jianqing WANG, "An Approach to Evaluate Electromagnetic Interference with a Wearable ECG at Frequencies below 1MHz" in IEICE TRANSACTIONS on Communications, vol. E98-B, no. 8, pp. 1606-1613, August 2015, doi: 10.1587/transcom.E98.B.1606.
Abstract: In this study, we propose a two-step approach to evaluate electromagnetic interference (EMI) with a wearable vital signal sensor. The two-step approach combines a quasi-static electromagnetic (EM) field analysis and an electric circuit analysis, and is applied to the EMI evaluation at frequencies below 1 MHz for our developed wearable electrocardiogram (ECG) to demonstrate its usefulness. The quasi-static EM field analysis gives the common mode voltage coupled from the incident EM field at the ECG sensing electrodes, and the electric circuit analysis quantifies a differential mode voltage at the differential amplifier output of the ECG detection circuit. The differential mode voltage has been shown to come from a conversion from the common mode voltage due to an imbalance between the contact impedances of the two sensing electrodes. When the contact impedance is resistive, the induced differential mode voltage increases with frequency up to 100kHz, and keeps constant after 100kHz, i.e., exhibits a high pass filter characteristic. While when the contact impedance is capacitive, the differential mode voltage exhibits a band pass filter characteristic with the maximum at frequency of around 150kHz. The differential voltage may achieve nearly 1V at the differential amplifier output for an imbalance of 30% under 10V/m plane-wave incident electric field, and completely mask the ECG signal. It is essential to reduce the imbalance as much as possible so as to prevent a significant interference voltage in the amplified ECG signal.
URL: https://globals.ieice.org/en_transactions/communications/10.1587/transcom.E98.B.1606/_p

Copy

@ARTICLE{e98-b_8_1606,
author={Wei LIAO, Jingjing SHI, Jianqing WANG, },
journal={IEICE TRANSACTIONS on Communications},
title={An Approach to Evaluate Electromagnetic Interference with a Wearable ECG at Frequencies below 1MHz},
year={2015},
volume={E98-B},
number={8},
pages={1606-1613},
abstract={In this study, we propose a two-step approach to evaluate electromagnetic interference (EMI) with a wearable vital signal sensor. The two-step approach combines a quasi-static electromagnetic (EM) field analysis and an electric circuit analysis, and is applied to the EMI evaluation at frequencies below 1 MHz for our developed wearable electrocardiogram (ECG) to demonstrate its usefulness. The quasi-static EM field analysis gives the common mode voltage coupled from the incident EM field at the ECG sensing electrodes, and the electric circuit analysis quantifies a differential mode voltage at the differential amplifier output of the ECG detection circuit. The differential mode voltage has been shown to come from a conversion from the common mode voltage due to an imbalance between the contact impedances of the two sensing electrodes. When the contact impedance is resistive, the induced differential mode voltage increases with frequency up to 100kHz, and keeps constant after 100kHz, i.e., exhibits a high pass filter characteristic. While when the contact impedance is capacitive, the differential mode voltage exhibits a band pass filter characteristic with the maximum at frequency of around 150kHz. The differential voltage may achieve nearly 1V at the differential amplifier output for an imbalance of 30% under 10V/m plane-wave incident electric field, and completely mask the ECG signal. It is essential to reduce the imbalance as much as possible so as to prevent a significant interference voltage in the amplified ECG signal.},
keywords={},
doi={10.1587/transcom.E98.B.1606},
ISSN={1745-1345},
month={August},}

Copy

TY - JOUR
TI - An Approach to Evaluate Electromagnetic Interference with a Wearable ECG at Frequencies below 1MHz
T2 - IEICE TRANSACTIONS on Communications
SP - 1606
EP - 1613
AU - Wei LIAO
AU - Jingjing SHI
AU - Jianqing WANG
PY - 2015
DO - 10.1587/transcom.E98.B.1606
JO - IEICE TRANSACTIONS on Communications
SN - 1745-1345
VL - E98-B
IS - 8
JA - IEICE TRANSACTIONS on Communications
Y1 - August 2015
AB - In this study, we propose a two-step approach to evaluate electromagnetic interference (EMI) with a wearable vital signal sensor. The two-step approach combines a quasi-static electromagnetic (EM) field analysis and an electric circuit analysis, and is applied to the EMI evaluation at frequencies below 1 MHz for our developed wearable electrocardiogram (ECG) to demonstrate its usefulness. The quasi-static EM field analysis gives the common mode voltage coupled from the incident EM field at the ECG sensing electrodes, and the electric circuit analysis quantifies a differential mode voltage at the differential amplifier output of the ECG detection circuit. The differential mode voltage has been shown to come from a conversion from the common mode voltage due to an imbalance between the contact impedances of the two sensing electrodes. When the contact impedance is resistive, the induced differential mode voltage increases with frequency up to 100kHz, and keeps constant after 100kHz, i.e., exhibits a high pass filter characteristic. While when the contact impedance is capacitive, the differential mode voltage exhibits a band pass filter characteristic with the maximum at frequency of around 150kHz. The differential voltage may achieve nearly 1V at the differential amplifier output for an imbalance of 30% under 10V/m plane-wave incident electric field, and completely mask the ECG signal. It is essential to reduce the imbalance as much as possible so as to prevent a significant interference voltage in the amplified ECG signal.
ER -