*** - Highly Relevant, ** - Moderately Relevant, * - Less Relevant,
NR - Not Relevant Abstract: This paper discusses some of the
research on risk estimation of EMI malfunction of medical devices done by
the McGill University Biomedical Engineering Group of Electromagnetic
Compatibility. The risk for EMI malfunction is summarized in a simple
equation. A few solutions to minimize the risk of medical device EMI
malfunctions are also proposed. Subjects: What is the Risk of EMI
Malfunction?; Potential Sources of EMI; Which Sources Have the Greatest
EMI Potential?; Measurement of the Electromagnetic Environment of
Hospitals: Fixed and Portable Sources; Medical Device Immunity to EMI;
Minimizing the Risk of EMI Malfunctions; Source - Device Separation
Distance; Current and Future EMI Potential Risk; EMI Risk Minimization:
The Next 5 to 10 Years and the Next 10 to 20 Years Note: Also in Chapter 1 and Chapter 4 Abstract: Many medical devices have
significant interference problems due to radiofrequency interference
(RFI) in the non clinical environment. This paper discusses the
measurement performed by the Center for Devices and Radiological Health
(CDRH) to determine the field strengths of common RF sources in this
area. The study showed that the field strength of distant transmitters,
user handheld transceivers, and local transmitters exceeded the 3V/m RFI
immunity level specified in the IEC 601-1-2 international medical device
electromagnetic compatibility standard. Subject: Introduction; Methods; Results;
Conclusions Note: Also in Chapter 1 Abstract: This paper describes the effects of
electromagnetic interference (EMI) on medical devices. It discusses the
various sources of electromagnetic interference such as power lines,
radio stations, cellular phones and walkie-talkies, while presenting
examples of hospital policies on the usage of transmitting devices. It
also provides excerpts of different standards dealing with EMI and EMC by
radio frequency fields and medical devices. Subjects: Sources of Electromagnetic
Interference; Susceptible Devices; Portable Telecommunication Devices;
Hospital Policies; Electromagnetic Compatibility; National and
International Standards Note: Also in Chapter 1 and Chapter 4 Abstract: The numerous reports on EMI in
electronic medical devices have triggered investigations into the
susceptibility of specific devices, the realization that EMI is a
potential hazard for electronic medical devices, and the development of a
CDRH plan to assure EMC in medical devices. An on-line version of
reporting EMI problems in medical devices is currently under
consideration at CDRH. Until then, EMI problem reports can best serve to
raise the awareness of the medical device community about the kind of
malfunctions that could arise and to identify medical devices and use
them in environments for which further investigation on EMI is needed. Subjects: Medical Device Problem Reporting;
Are Problem Reports Verified?; What Is Actually EMI?; The Changing
Electromagnetic Environment; How Much Of A Problem Is EMI?; What Has
the FDA Done About EMI?; Accessing FDA Problem Reports; Suggestions for
Medical Device Manufacturers; Suggestions for Health-Care Facilities;
Examples EMI Problem Reports Note: Also in Chapter 4 Abstract: Due to the increasing use of high
power FM radio and VHF television, the Center for Devices and
Radiological Health (CDRH) conducted an experiment to
determine the radiofrequency (RF) susceptibility of an apnea monitor.
The experimental method include connecting the monitor to a
saline-filled, full-size model of an adult human and conducting
measurements at an outdoor electromagnetic (EMC) test facility. The
results showed that the RF susceptibility of an apnea monitor increased
by approximately 8 to 15 dB when its leads and electrodes were connected
to the model. Subject: Introduction; Exposure System; Human
Model; Medical Devices; Diagnostic System; RF Interference Test Methods;
Results; Conclusions Abstract: This report discusses a study
performed to collect data for radiated EMI and conducted EMI in different
hospital environments in two major hospitals. The radiated measurements
were taken using a Model 2712 spectrum analyzer, calibrated EMI antenna,
and a Model 3004 RF field intensity meter. The conducted measurements
were taken using a single-phase power disturbance analyzer. The results
showed that the main sources of radiated EMI were intentional radiators
such as telemetry and paging devices, handheld radios, and wireless
phones. The study also found the electrosurgical units (ESUs) to be a
main source of radiated EMI. However, low levels of EMI was found to be
emitted from lasers, x-rays, and other high-energy equipment. There was
also minimal conducted EMI resulting from power disturbances. Subjects: The Elements of EMI; Test Methods;
Test Results; Discussion Note: Also in Chapter 1 Abstract: The possibility of disruption of
hospital equipment due to interference from cellular mobile phones is a
matter of grave concern. Increasingly, several hospital policies
restrict the usage of phones in areas such as Intensive Care Units.
Though there is no concrete evidence to prove that the interference is
due to phones, the potential damage is undeniable. Since cellular phones
are highly mobile and can be brought to the near vicinity of sensitive
equipment, any disruption caused may not be correctly attributed to
them. This article discusses the testing of analog and digital cellular
phones on medical equipment like syringe pump, infusion pump, pulse
oximeter, and monitor. Subjects: Problem; Equipment Tested; Test
Procedure Note: Technicians Abstract: This paper reports a study conducted
to test the effect of EMI from wireless telecommunication devices on
fifty medical devices chosen from fourteen medical device groups. The
study utilized four two-way radios and one analog cellular phone. The
results showed that these wireless telecommunication devices can cause
some medical devices to malfunction. The malfunctions due to EMI were
grouped into five different categories. Subjects: EMI Problems Reported in Canada; EMI
Screening Tests; Results; Discussion; Conclusion Abstract: Degradation of medical devices due
to electromagnetic interference can be harmful for patient safety.
Additional information is needed regarding circumstances in health care
environments in which electromagnetic field strengths are expected to be
high, such as emergency/transport. In ambulances, the requirement that
medical devices and communications equipment function properly in close
proximity is extremely critical. This study focuses on EM fields in and
around ambulances under realistic conditions. The results indicate that
the ambulance environment presents a considerable challenge to medical
devices specifically used for emergency medical care. Subjects: Ambulance Specifications; Methods;
Results and Discussions; Ambient Field Strength Measurements; Ambulance
Field Strength Measurements; Human Exposure Considerations Abstract: This paper describes the results of
a survey which has been done by the Medical Devices Bureau. Eight
monitoring and therapeutic medical devices were tested. The
susceptibility of these devices to EMI was determined by any change in
device function, including failure, distortion of displayed information,
erroneous readout or activation of an alarm. The tests were done using
the IEC standard 801-3 (1984) and the frequency range was extended to
2000 MHz to take into account the wide range of radio transmitters and
radio stations in use today. All medical devices tested were found to be
susceptible to radiated electric fields of varying strengths and
frequencies. Subjects: Biomedical Equipment; Equipment
Testing; Radio Frequency Spectroscopy; Electromagnetic Wave Interference;
Monitoring; Calibration; Amplitude Modulation; Electric Field Effects;
Frequencies; Cellular Telephone Systems; Radio Abstract: A study was conducted to assess the
effects of electromagnetic environmental (EME) potential hazard due to
fixed external sources on medical devices in five Montreal hospitals.
Field strength was measured inside and outside the five hospitals using
industry standard techniques at frequencies 30 MHz to 1000 MHz, and the
field measurement was then compared to fields predicted using
line-of-sight and hybrid methods. The result found that electromagnetic
interference (EMI) caused medical device malfunction although the
measured fields were below 3 V/m. For field prediction, the line-of
sight method predicted fields to within 20 dB of the measured fields
while hybrid method predicted fields to within 10 dB. Subject: Introduction; Methods; Results;
Discussion and Summary Abstract: This paper discusses the
interference caused by analog and digital cellular phones on implantable
cardiac pacemakers. The details of a study conducted to ascertain the
interference of cellular telephones on cardiac pacemakers are described.
In vitro testing was employed and the phones were placed in the close
vicinity of four pacemakers. It was found that all four pacemakers
exhibited some kind of interference.
Seven different types of cellular phones, operating in the frequency
range of 800-900 MHz were employed in the study. Subjects: Introduction; Materials and Methods;
Experimental Setup; Results and Conclusions Abstract: This report summarizes the results
of the large-scale in vitro investigation
interaction between wireless phones and cardiac pacemakers conducted by
the Center for the Study of Wireless Electromagnetic Compatibility at the
University of Oklahoma. The research focused on testing 29 pacemaker
models with 5 different phone standards to evaluate the amount of
interaction between wireless phones and pacemakers as well as to identify
those factors which had a significant influence on the level of
interaction. Subjects: Background; Method; Conclusions,
Future Directions; Order Form Abstract: This report summarizes the results
of the phone-pacemaker planar separation study which is an extension of
earlier research conducted by the Center for the Study of Wireless
Electromagnetic Compatibility at the University of Oklahoma. This second
phase of testing was conducted to further define the minimum planar
separation distance of the phone and pacemaker needed to avoid
interaction. Subjects: Background; Method; Conclusions Abstract: This paper is a concise version of a
study done to investigate the interference of implanted cardiac
pacemakers with wireless communication devices. The objective of the
study was to determine the interference effects which occur at different
spatial positions from the surface of a pacemaker and to ascertain if
filtering technology can reduce these interference effects. This article
also provides the methodology and results of this study. Subjects: Abstract; Objectives; Test Protocol;
Results; Recommendations Abstract: EMI-induced degradation of medical
devices could adversely affect medical diagnosis and patient treatment
and at times can be fatal. This paper provides information concerning
engineering design of commonly used medical electronic devices in India,
and their performance within the hospitals electromagnetic environment.
It also focuses on the sources of EMI and its effects on the commonly
used medical equipment. Subjects: Electromagnetic Environment;
Electromedical Equipment Causing EMI; Electromedical Equipment
Susceptible to EMI; EEG; EMG; Cardiac Pacemaker; Design Aspects to
Achieve EMC; Power Supply Considerations; EMC Standard for Medical
Equipment Abstract: This executive summary presents the
results of the clinical trials of the Hearing Aid - Wireless Phone
Interaction study completed by the University of Oklahoma Wireless EMC
Center. To date in the United States, this study is the most
comprehensive scientific effort to involve a diverse group of hearing aid
users to determine the degree of interaction between hearings aids and
wireless phones. Subjects: Background; Scope of the Clinical
Trials; Results; Future Research; Order Form Abstract: This study presents the results of a
study done at the University of Oklahoma to develop a standard
interference signal that can be used to test all hearing aids. It was
shown that the IRIS signals had similar pattern defined by the phone
technology for all hearing aids. In this experiment, five IRIS signal
levels for each of the three phone technologies were mixed with speech at
65 dB SPL (L) to test the speech intelligibility of 24 hearing-impaired
people subjected to wireless phone interference. Subjects: Executive Summary; Order Form Abstract: The purpose of this research was to
evaluate the interaction of digital wireless telephones with hearing aids
at various distances. Four behind-the-ear (BTE) and four in-the-ear
(ITE) hearing aids were tested with five different types of digital
wireless phones
(GSM, PCS-1900, NADC, CDMA, TDMA). The study found that all the phones
tested produced similar interference level within 2 cm of hearing aids.
It also proved that the
interference-induced sound pressure level (SPL) from code division
multiple access (CDMA) based system reduced rapidly with distance as
compared to those from the division multiple access (TDMA) based system. Subject: Introduction; Methods; Results;
Discussion Abstract: This report summarizes the results
of an in vitro investigation of the interaction between wireless phones
and implantable cardioverter defibrillators (ICDs) by the Center for the
Study of Wireless Electromagnetic Compatibility at the University of
Oklahoma. This study comprised Phase I of the Centers ICD research, and
focused on determining the amount of interaction between wireless phones
and ICDs, and identifying those factors which had a significant influence
on the level of interaction. Subjects: Background; Method; Scope of This
Study; Conclusions; Future Research; Order Form Abstract: Sensitive patient cables are
susceptible to electromagnetic interference. This article focuses on
radiated interference issues surrounding patient cable terminations.
Most of the traditional solutions are not effective with such
terminations. Suppressing EMI at the patient connection can be
complicated and requires a lot of experimentation. This article
discusses the challenges and possible solutions to the problem. Subjects: Challenge; Solutions; Filters;
Shields; Chassis Ground; Conclusion Abstract: This paper addresses the issue of a
radiant heater, a critical-care medical device that malfunctioned
"silently" and discusses its implications. The malfunction occurred
within 1-2 m. of a 146 MHz walkie-talkie (100mW). A more complete
test-chamber assessment of EMI susceptibility proved that the heater
malfunctioned at electric field strengths above 0.3 -1 V/m over four
roughly 50 MHz bands between about 10 and
600 MHz. The malfunction was due to EMI from near-by fixed source FM
transmission antennas. The device had probably been malfunction for
months but was not detected. Due to the difficulty of detecting such
malfunction, awareness, vigilance and understanding of "silent"
malfunctions are essential to prevent serious consequences. Subject: Malfunction History; Methods; Results
- Device Function in Repair Shop, Partial Susceptibility Testing, More
Complete Susceptibility Testing, Malfunction-Site Electromagnetic
Environment; Discussion, Discussion - Patterns of EMI Malfunctions Not
Recognized, Unfamiliarity With Electromagnetic Environment, Alarms
Misinterpreted, Unawareness of, and Non-Vigilance for, EMI Malfunctions,
Significance Abstract: There have been several incidents
related to unintended movement of powered wheelchairs and scooters for
the last two years. This article discussed the study done by the Center
for Devices and Radiological Health (CDRH) to investigate the
susceptibility of those devices to electromagnetic interference (EMI).
The study proved that the powered wheelchair and scooter exhibited some
degree of susceptibility to exposure fields. Subject: Introduction; Methods; Results
The following abstracts have been categorized into:
3.4.1 Sources of Electromagnetic Interference
3.4.2 Interaction of Wireless Phones and Medical Devices
(General Studies)
3.4.3 Interaction of Wireless Phones and Medical Devices
(Specific Studies)
3.4.1 Sources of Electromagnetic Interference
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SOURCES AND VICTIMS: THE POTENTIAL MAGNITUDE OF THE ELECTROMAGNETIC
INTERFERENCE PROBLEM
Bernard Segal
Electromagnetic Compatibility for Medical Devices: Issues and Solutions
1996
p 24 39
Full Version Of Article Reprinted With Permission From Dr. Bernard Segal
and AAMI.
GO BACK TO TOP
SOURCES OF RADIOFREQUENCY INTERFERENCE FOR MEDICAL DEVICES IN THE NON
CLINICAL ENVIRONMENT
Howard Bassen, Paul Ruggera, Jon Casamento, and Donald Witters
Institute of Electrical and Electronics Engineers
1994
p 896 - 897
Full Version Of Article Reprinted With Permission From IEEE. Copyright ©
1994 IEEE.
GO BACK TO TOP
WALKIE-TALKIES AND CELLULAR TELEPHONES: THE HAZARDS OF ELECTROMAGNETIC
INTERFERENCE IN HOSPITALS
Kok-Swang Tan and Irwin Hinberg
Leadership
v 3 n 3
p 11 15
Full Version Of Article Reprinted With Permission From Kok-Swang
Tan.
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WHAT CAN/SHOULD WE LEARN FROM REPORTS OF MEDICAL DEVICE ELECTROMAGNETIC
INTERFERENCE?
Jeff Silberberg
Proceedings of a Workshop on Electromagnetics, Healthcare and Health
1995
p 10 19
Full Version Of Article Reprinted With Permission From Proceedings of a
Workshop on Electromagnetics, Healthcare and Health. Copyright © 1995
IEEE.
3.4.2 Interaction of Wireless Phones and Medical
Devices (General Studies)
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CHANGES IN THE SUSCEPTIBILITY OF A MEDICAL DEVICES RESULTING FROM
CONNECTION TO A FULL-SIZE MODEL OF A HUMAN
Howard Bassen, Paul Ruggera, and Jon Casamento
Proceedings of the Annual International Conference of the IEEE
Engineering in Medicine and Biology Society
1992
p 2832 - 2834
Full Version Of Article Reprinted With Permission From Proceedings of the
Annual International Conference of the IEEE Engineering in Medicine and
Biology Society. Copyright © 1992 IEEE.
GO BACK TO TOP
ELECTROMAGNETIC INTERFERENCE IN THE HOSPITAL ENVIRONMENT
William D. Kimmel and Daryl D. Gerke
Medical Device and Diagnostic Industry
May 1995
p 97 101
Full Version Of Article Reprinted With Permission From Medical Device and
Diagnostic Industry. Copyright © 1995 Canon Communications LLC.
GO BACK TO TOP
INTERFERENCE TO MEDICAL EQUIPMENT FROM MOBILE PHONES
M.P. Robinson, I.D. Flintoft, and A.C. Marvin
Journal of Medical Engineering and Technology
v 21 n 3 - 4 May - August 1997
p 141 146
Full Version Of Article Reprinted With Permission from Journal of Medical
Engineering and Technology. Copyright © 1997 Taylor & Francis.
GO BACK TO TOP
INVESTIGATION OF ELECTROMAGNETIC INTERFERENCE WITH MEDICAL DEVICES IN
CANADIAN HOSPITALS
Kok-Swang Tan and Irwin Hinberg
Proceedings of a Workshop on Electromagnetics, Healthcare and Health
1995
p 20 23
Full Version Of Article Reprinted With Permission From Proceedings of a
Workshop on Electromagnetics, Healthcare and Health. Copyright © 1995
IEEE.
GO BACK TO TOP
MEASUREMENT OF RADIOFREQUENCY FIELDS IN AND AROUND AMBULANCES
William S. Boivin, Sean M. Boyd, John A. Coletta, and Lesley M. Neunaber
Biomedical Instrumentation & Technology
v 31 n 2 March - April 1997
p 145 154
Full Version Of Article Reprinted With Permission From Biomedical
Instrumentation & Technology. Copyright © 1997 AAMI.
GO BACK TO TOP
RADIOFREQUENCY SUSCEPTIBILITY TESTS ON MEDICAL EQUIPMENT
Kok-Swang Tan and Irwin Hinberg
Proceedings of the Annual International Conference of the IEEE
Engineering in Medicine and Biology Society
1994
p 998 999
Full Version Of Article Reprinted With Permission From Proceedings of the
Annual International Conference of the IEEE Engineering in Medicine and
Biology Society. Copyright © 1994 IEEE.
GO BACK TO TOP
THE MEASURED & PREDICTED ELECTROMAGNETIC ENVIRONMENT AT URBAN HOSPITALS
P. Vlach, B. Segal, and T. Pavlasek
Institute of Electrical and Electronics Engineers
1995
p 4 7
Full Version Of Article Reprinted With Permission From IEEE. Copyright ©
1995 IEEE.
3.4.3 Interaction of Wireless Phones and Medical Devices (Specific
Studies)
3.4.3.1 Cardiac Pacemakers
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ELECTROMAGNETIC NEAR FIELD INTERFERENCE WITH IMPLANTABLE MEDICAL DEVICES
Roger Carrillo, Oscar Garay, Q. Balzano, and Michael Pickels
IEEE International Symposium on Electromagnetic Compatibility
August 1995
Full Version Of Article Reprinted With Permission From IEEE. Copyright ©
1995 IEEE.
GO BACK TO TOP
IN VITRO STUDY OF THE INTERACTION OF WIRELESS PHONES WITH
CARDIAC PACEMAKERS
Robert E. Schlegel, Shivakumar Raman, Hank Grant, and A. "Ravi" Ravindran
Publication of the Center for the Study of Wireless Electromagnetic
Compatibility, University of Oklahoma, Norman
EMC Report 1996 - 3
p 1 5
Full Version Of Article Reprinted With Permission From The University of
Oklahoma Wireless EMC Center. Copyright © 1996 University of
Oklahoma.
GO BACK TO TOP
IN VITRO STUDY OF THE INTERACTION OF WIRELESS PHONES WITH
CARDIAC PACEMAKERS - PHASE II: PLANAR SEPARATION EFFECTS OF AIR
Hank Grant and Robert E. Schlegel
Publication of the Center for the Study of Wireless Electromagnetic
Compatibility, University of Oklahoma, Norman
EMC Report 1998 - 2
p 1 3
Full Version Of Article Reprinted With Permission From The University of
Oklahoma Wireless EMC Center. Copyright © 1998 University of
Oklahoma.
GO BACK TO TOP
IN VITRO TESTING OF IMPLANTED CARDIAC PACEMAKERS FOR RADIOFREQUENCY
INTERFERENCE FROM WIRELESS COMMUNICATION DEVICES
Kok-Swang Tan and Irwin Hinberg
CTIA-Workshop on Electromagnetic Compatibility in Health Care and Cardiac
Pacemakers
Full Version Of Article Reprinted With Permission From Kok-Swang
Tan.
3.4.3.2 Electrocardiography
GO BACK TO TOP
EMI SUSCEPTIBILITY CHARACTERISTICS OF ELECTROMEDICAL EQUIPMENT IN A
TYPICAL HOSPITAL ELECTROMAGNETIC ENVIRONMENT WITH PARTICULAR REFERENCE TO
ELECTROCARDIOGRAPHY
S. Bandopadhyay and James K. Varkey
1995 International Conference on Electromagnetic Interference and
Compatibility (INCEMIC): Conference Proceedings
December 1995
p 266 272
Full Version Of Article Reprinted With Permission IEEE. Copyright © 1995
IEEE.
3.4.3.3 Hearing Aids
GO BACK TO TOP
EVALUATION OF THE INTERACTION BETWEEN WIRELESS PHONES AND HEARING AIDS -
PHASE 1: RESULTS OF THE CLINICAL TRIALS
A. "Ravi" Ravindran, Robert E. Schlegel, Hank Grant, Pamela Matthews, and
Perma Scates
Publication of the Center for the Study of Wireless Electromagnetic
Compatibility, University of Oklahoma, Norman
EMC Report 1996 - 2
p 1 - 3
Full Version Of Article Reprinted With Permission From The University of
Oklahoma Wireless EMC Center. Copyright © 1996 University of
Oklahoma.
GO BACK TO TOP
EVALUATION OF THE INTERACTION BETWEEN WIRELESS PHONES AND HEARING AIDS -
PHASE II - B: CLINICAL DETERMINATION OF THE SPEECH - TO - INTERFERENCE
RATIO
Shalini Srinivasan, Robert E. Schlegel and Hank Grant
Publication of the Center for the Study of Wireless Electromagnetic
Compatibility, University of Oklahoma, Norman
EMC Report 1997 - 2
p 1
Full Version Of Article Reprinted With Permission From The University of
Oklahoma Wireless EMC Center. Copyright © 1997 University of
Oklahoma.
GO BACK TO TOP
HEARING AID ELECTROMAGNETIC INTERFERENCE FROM DIGITAL WIRELESS TELEPHONES
Marlene Skopec
June 1998
p 235 - 239
Full Version Of Article Reprinted. U.S. Government Work Not Protected
By Copyright.
3.4.3.4 Implantable Cardioverter Defibrillators
GO BACK TO TOP
IN-VITRO STUDY OF THE INTERACTION OF WIRELESS PHONES WITH IMPLANTABLE
CARDIOVERTER DEFIBRILLATORS
Glenn W. Kuriger, Hank Grant, and Robert E. Schlegel
Publication of the Center for the Study of Wireless Electromagnetic
Compatibility, University of Oklahoma, Norman
EMC Report 1998 - 1
p 1 5
Full Version Of Article Reprinted With Permission From The University of
Oklahoma Wireless EMC Center. Copyright © 1998 University of
Oklahoma.
3.4.3.5 Patient Cable
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EMI AT THE PATIENT CABLE
William.D Kimmel and Daryl D. Gerke
Medical Device and Diagnostic Industry
January 1998
p 88 92
Full Version Of Article Reprinted With Permission From Medical Device and
Diagnostic Industry. Copyright © 1998 Canon Communications LLC.
3.4.3.6 Radiant Heaters
GO BACK TO TOP
"SILENT" MALFUNCTION OF A CRITICAL-CARE DEVICE CAUSED BY ELECTROMAGNETIC
INTERFERENCE
Bernard Segal, Stephen Retfalvi, and Tomas Pavlasek
Biomedical Instrumentation and Technology
v 29 n 4 July/August 1995
p 350 - 354
Full Version Of Article Reprinted With Permission From Biomedical
Instrumentation & Technology. Copyright © 1995 AAMI.
3.4.3.7 Wheelchairs and Scooters
GO BACK TO TOP
ELECTROMAGNETIC COMPATIBILITY (EMC) OF POWERED WHEELCHAIRS AND SCOOTERS
Donald M. Witters and Paul S. Ruggera
Institute of Electrical and Electronics Engineers
1994
p 894
Full Version Of Article Reprinted With Permission From IEEE. Copyright ©
1994 IEEE.
For more information, please contact the Wireless EMC
Center. Office phone number: 405-325-2429, Internet
email address: emc@ou.edu
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