NEWSLETTER DISTRIBUTION C63 JULY 19 to 21 MEETING SERIES C63.4 SEMINAR/WORKSHOP EMC IMMUNITY GUIDANCE INTERNATIONAL STANDARDS DoD/INDUSTRY STUDY on USE of
COMMERCIAL STANDARDS SC-8 ACTIVITIES C63 OFFICERS’ DIRECTORY
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Distribution is limited to C63 Committee Members, IEEE EMC Society Directors, and US TAGs for CISPR & TC77. Recipients may share the information with colleagues. The Newsletter in its entirety, or in part, should not be sent to public bulletin board systems.
Contributions of readers to the content, as well as general comments will be welcome. ****
LOCATION: AT&T Wireless Redmond Town Center Facility 16221 NE 72nd Way Redmond WA, 98052
(Wed & Thur, Bldg. 3, 2nd Floor, Apollo Meeting Room. Fri, Bldg. 3, 1st Floor, Explorer Training Room)
MEETING SCHEDULE:
Wed 19 July SC/8 0900-1200 SC/6 1300-1500 SC/3 1500-1700 C63 Steering 1800-1900 (Invitation only)
Thur 20 July SC/1 0800-1200 C63 1300-1700 USEMCSC BOD 1800-1900 (Invitation only)
Fri 21 July C63 0900-1200
(Note: Next C63 meeting is scheduled for November 1 to 3 in Piscataway New Jersey) *****
A comprehensive 2-day C63.4 seminar/workshop will be conducted by Don Heirman, Bob Hofmann and Art Wall on:
August 18-19 in conjunction with the IEEE EMC Symposium at the Washington Hilton and Towers in Washington, DC and,
September 7-8 in conjunction with EMC Europe 2000 in Brugge (Belgium).
This seminar is designed to increase your understanding of the methods of measurement of radio-noise emissions from low voltage electrical and electronic equipment in the range of 9 kHz to 40 GHz as it applies to determining compliance with FCC technical standards for digital devices and other similar product requirements. A comparison of CISPR 22 (1997) with C63.4-1992 and C63.4-2000 (soon to be published) will also be included.
Contact Janet O’Neil, e-mail j.n.oneil@ieee.org *****
C63’s Subcommittee 6 has prepared checklists for use by approval agencies in accrediting EMC Laboratories. These checklists address specific criteria to evaluate the capability of the prospective laboratory facility and to determine the competency of the laboratory personnel for performing the required measurements. This guidance document will be a significant help to get your lab ready for the NIST and International or other agency inspector. The 62 page document contains checklists for European Standards 61000-4-2, 3, 4, 5, 6, 8 and 11. It is available from the US EMC Standards Corporation (which manages the affairs of the Accredited EMC Committee C63) at a cost of $50.00 per copy (add $20.00 shipping for outside US).
Contacts: Daniel Hoolihan (hoolihan@emcexpert.com) or Herbert Mertel (hmertel@ieee.org).
Note: SC-6 is currently developing checklists for other EMC standards such as CISPR 11, 13, 20, 22, 24 and EN 61000-3-2, -3.
CISPR/TR 16-3 (2000-05) Specification for radio disturbance and immunity measuring apparatus and methods – Part 3: Reports and recommendations of CISPR was released on 30 May 2000. It contains recommendations on statistics of disturbance complaints, on the significance of CISPR limits, on determination of CISPR limits and other specific reports which were for some time published in CISPR 7 and 8.
IEC’s new 51 page EMC Guide is available as a free download from IEC. (http://www.iec.ch/newslt-e.htm#On-line publications)
CISPR Working Groups A & G have in review a number of draft committee documents related to:
*an amendment to CISPR 24 Clause 6 and a new Annex on test set-up of ITE for immunity measurements
*differentiation between EUT & ambient signals in emission measurements
*measurement uncertainties when determining compliance with a limit
*testing in TEM waveguides
*meter time constants of the average detector for the measurement of intermittent, unsteady and drifting narrowband disturbances
*uncertainty in emission voltage measurements
*a possible new subclause in CISPR 16-2 proving information on making and recording automated emission measurements
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A final draft of the Defense/Industry E3 Standards Committee’s Engineering Practices Study was released (earlier this year) for comment by 30 June. This document is the result of a cooperative effort between DoD and US industry with a goal of assessing the suitability of using equipment qualified to commercial EMC standards for use in military applications. MIL-STD-461E was used as a basis for comparison. Dr. Ralph Showers (C63 Chair) was the principle representative for industry.
Following is an article on the evolution of military standards leading to the current MIL-STD-461E:
By Herbert Mertel andWarren Kesselman
1 The Early Years - Control of Ignition interference
The US military first encountered Radio Frequency Interference (RFI) some time prior to World War I when a radio was first installed on a vehicle. However, little is known about early efforts to address RFI problems until the early 1930s. The IRE (Institute of Radio Engineers) 1932 Proceedings included a paper on “Electrical Interference in Motor Car Receivers”. The first military specification was published by the US Army Signal Corps in 1934 as SCL-49 entitled “Electrical Shielding and Radio Power Supply in Vehicles”. That document “protected” radio receivers from interference by requiring shielding of the vehicle ignition system, regulator and generator. The requirement was simply that the vehicle operation will not “disturb” radio reception. With the increased use of mobile radio communications, it became apparent SCL-49 was inadequate. In 1942 it was superseded by specification 71-1303, “Vehicular Radio Noise Suppression” that addressed (in addition to shielding) the use of filters, by-pass capacitors, resistor-suppressors, bonding, grounding and proper wire routing. This specification also defined an instrumentation system and a limit. During the 1940s military standards were principally concerned with RFI suppression components for internal combustion engines and electrical machinery. In 1945 a joint Army-Navy (Air Force not yet “born”) standard JAN-I-225 entitled “Interference Measurement, Radio, Methods of, 150 Kilocycles to 20 Megacycles (For components and complete assemblies) was issued.[ 1 - 3]
The subsequent succession of military EMC specifications closely follows the evolution of our electrotechnology. Initially, military specification limits for radio frequency interference were established to protect the minimum usable field strength on board vehicles for land, sea, and air. As more sensitive equipment was developed, susceptibility (immunity) limits were established. With the space age came the concept of electromagnetic compatibility within small platform systems and also between systems. As a consequence, the equipment and system specifications became more general to include all types of electrical and electronic equipment that require application of EMC techniques during the design, development, production, installation, and operational states.
2 1950 - 1965: A Proliferation of Interference and Susceptibility Specs
In the 1950s and up to 1965, each major military agency imposed its own (electromagnetic interference (EMI)/ EMC specification in the procurement of electronic systems and equipment. For instance, the Air Force used MIL-1-6181 and MIL-1-26600, the Navy used MIL-I-16910, and the Army used MIL-I-11748 and MIL-E-55301(EL). These specifications limited the amount of conducted and radiated EMI emissions and set susceptibility levels which systems and equipment must reject. The specifications also set forth the test configurations and techniques needed to demonstrate compliance with the requirements therein.
The existence and application of different EMC specifications for each service caused quite a dilemma. They were significantly different from each other, so that when a component was designed to meet one specification, it usually had to be redesigned and tested to meet another. The frequency ranges covered were different and the limits for overlapping frequencies varied. More significantly, each specification required the use of different test equipment, making it quite expensive for an organization to be fully equipped to test to all EMC specifications.
The problem was compounded by additional specifications for specific systems, such as Minuteman AFBSD-62-87 initiated by the Boeing Company; GSFCS-523-P-7 prepared by Genisco under contract from Goddard Space Flight Center for Aerospace Ground Equipment (AGE); and those issued by technical centers, such as MSFC-SPEC-279 issued by the Marshall Space Flight Center and MIL-STD-1541 issued by the USAF/SAMSO . It became obvious that there was a need to limit these different specifications and the generation of one unified standard to serve all government and military agencies.
The first attempt to issue a specification which would be acceptable to all branches of the government was the publication of MILSTD-826 in January 1964. This document presented a new set of limits. However, this effort was ill-fated and MIL-STD-826 was used only by the USAF. [4, 5]
In the1960s the US Department of Defense (DoD) enacted a comprehensive Defense Radio Frequency Compatibility Program (later renamed Electromagnetic Compatibility Program) that focused the Military Services R&D programs “to provide a means whereby electromagnetic compatibility should be “built into” military communications-electronics equipment in the research and development stage”. In 1966, EMC personnel of the three military departments jointly drafted standards addressing the interference reduction needs of the entire Department of Defense. That effort culminated in 1967 in the issuance of Military Standards 461, 462 and 463. As a result, approximately 20 basic and subsidiary specifications were superseded. The 461 document focused on requirements and the 462 standard prescribed measurement methodology. Definitions and acronyms were contained in 463.
Considerable revision was required and MIL-STD-461A was issued in August 1968. MIL-STD-461 was accepted by the joint services and was also used by many other countries. Eventually, the different military agencies (Army, Air Force, and Navy) found many items to their dissatisfaction, and thus many revisions were issued by each of the three services until 1989 the most noted difference was the "Pink Copy" issued by the Army.
4 - 1990 - 2000: Military EMC Specifications Mature
An effort was started in 1990 by the Tri-Service EMC Committee to prepare an updated MIL-STD-461 and MIL-STD462. MIL-STD-463 was withdrawn and definitions were referenced in American National Standards Institute (ANSI) C63.14 “Standard Dictionary for Technologies of Electromagnetic Compatibility (EMC), Electromagnetic Pulse (EMP) and Electrostatic Discharge (ESD)”. [6, 7]
Since the 1970s EMC personnel of the US Army, Navy and Air Force have periodically met and upgraded MIL-STD-461 and 462. The latest revision (1999) consolidated the two standards (Limits and Measurement Methods) into one standard: MIL-STD-461E “Requirements for the Control of Electromagnetic Interference Characteristics of Subsystems and Equipment”. This latest edition is an “interface” standard of requirements to provide reasonable assurance (during development) that a system, subsystem or equipment will be compatible with its anticipated electromagnetic environment. [8]
The most significant changes in MILSTD-461D/-462D and the subsequent MIL-STD-461E as compared with the previous MIL-STD-461C are as follows:
*Broadband emission tests are deleted. *Measurement (6 dB) bandwidths are specified. *Radio frequency (RF) susceptibility scan times
are specified. *The 50 Ω line impedance stabilization network
(LISN) is used for conducted emission. *Test setup calibration is required. *Absorber in shielded room is specified. *Bulk cable injection is specified. *Conducted emission measurements stop at 10
MHz. *Explanatory appendices were added to MILSTD-461D and MIL-STD-462D. *Receiver susceptibility tests must be defined for
each procurement. *MIL-STD-463 was canceled. American National Standards Institute (ANSI) C63.14 is referenced for definitions.
The most valuable sections of these two specifications and of MIL-STD-461E are the appendices, which give the technical rationale for the limits and measurement procedures. These appendices should be read first because the material gives the logic behind the requirements. Although it is not customary that military specifications are accredited to an author; the appendices of MIL-STD-461D/-462D as well as of -461E are accredited to one of the main contributors of the -461d and -461E rewrite: Mr. John Zentner of the Air Force Systems Division of Wright-Patterson Air Force Base.
The technical work was completed in November 1992. The two documents were published in January 1993 as MIL-STD-461 and MIL-STD-462D [6, 7]. The work for MIL-STD-461E was completed in 1999. The basic concepts of 461 standards were adopted by several non-US military organizations and also influenced national and international standardization efforts
5 - Progress and Future of Military EMC specifications
Thus, over the past seven decades, US Military EMC Standards have evolved from a simple beginning to keep pace with the “technology explosion” and the resultant complex electromagnetic environment. The MIL-STD-461 D requirements (limits) and MIL-STD-462D test methods as well as the new "Interface Standard" MIL-STD-461E were developed by approximately 15 U.S. government and industry experts during the 1990 to 1999 time period under the leadership of Mr. Stephen Caine, USN/SPAWAR, ret..
However, the development of EMC specifications is never finished since the technology requiring compatibility constantly changes. Since 1998 on the Defense/Industry E3 Standards Committee has been trying to find a compromise between the (1) Policy of DOD to use commercial EMC standards whenever possible and (2) the use of MIL-STD-461E. The work is continuing at the time when this paper was prepared (May, 2000). However, the work to-date seems to indicate that there is very limited overlap of the military vs. the commercial EMC requirements. The EMC requirements of the military pertain to small metallic platforms with unique requirements that are distinct from the commercial EMC efforts.
References:
[1] Henning, E. (1944) “Vorschriften für die Funkentstörung von Geräten und Anlagen der Wehrmacht,” Einfürung zu VDE 0878, Vol. 65, pp. 5-6. Elektrotechnische Zeitulg (ETZ), Berlin.
[2} Joint Army-Navy Specification (1945). “Methods Of Radio Interference Measurement, JAN-I-225. 150 kc to 20 Mc, Army No. 71-3233, Navy No. 16-I-14
[3] Army-Navy Aeronautical Specification (1947). “Propeller Systems Radio Interference Limits,” AN-1-40.
[4] La Montagne, R. (1976). Intrasystem EMC Analysis Program. IEEE Int. Symposium Electromagnetic Compatibility, 1976;pp. 244245. Washington, DC.
[5]Interference Technology Master (1971). “The Origin of Military EMC Specifications.” ITEM, pp.50-53. Plymouth Meeting, PA. Robert D. Goldblum, Editor.
[6] Military Standard (1993). “Requirements for the Control of Electromagnetic Interference Emissions and Susceptibility,” MIL-STD-461D. Available from Naval Publications and Forms Center, Attention: NPODS, 700 Robbins Avenue, Philadelphia, PA 19111-5093.
[7] Military Standard (1993). “Measurement of Electromagnetic Interference Characteristics,” MILSTD-462D. (Companion document to MILSTD461 D.)
[8] Military Standard (1999). “DoD Interface Standard, requirements for the Control of Electromagnetic Interference Emissions and Susceptibility”, MIL-STD-461E
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Following are items taken from SC-8’s draft March 2000 Minutes:
based on the original protocol devised in 1998, but actual medical device cables will be used instead of a shielded, twisted pair data cable. The new protocol will utilize the same two simulated human models composed of Plexiglas cylinders filled with saltwater. One model (full size) has a length of 1.5 m. The other model's length is one-half of the full-size model. These models will be individually tested as follows. For each model, two chest electrodes will be connected at the input end of a tin-lead, shielded apnea monitor cable. The chest electrodes will be immersed in the saltwater of the model in the chest region. RF voltage measurements will be made at the output terminals of the apnea monitor leads after connecting them to an RF matching transformer. The output of the transformer will be connected to a spectrum analyzer to observe the possible resonance conditions. This work will be performed at Underwriters Laboratories in Melville NY, the same laboratory that performed recent experiments using the same models.
Work is continuing at the FDA labs in Rockville Maryland using finite difference times domain computer modeling to calculate the voltages induced on patient connected leads when connected to a full-size and a half size model of a human. This modeling, once it is perfected, has the advantage of allowing many different configurations to be tested quickly. In addition, the computer model can be used to simulate leads and a detailed, realistic model of the human body. This model has all of the precise electrical properties of the human body tissues for each organ and region of the body.
3. Jeff Silberberg gave an update on FDA activity. They are working with a pacemaker committee to develop standards for testing from 450 MHz to 2 GHz and below 30 MHz. They have an inter agency project with the FAA on metal detectors. With respect to medical telemetry, they are awaiting action from the FCC on the 450 to 460 MHz band. Jeff stated that if manufacturers move to the new bands, safety will be presumed. If they do not, then they must demonstrate to the FDA safety and effectiveness.
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Dr. Ralph M. Showers, Chairman (showers@ee.upenn.edu) Edwin L. Bronaugh, Vice-Chairman (Edwin.Bronaugh@icn.siemens.com) Patricia Gerdon, IEEE C63 Secretariat, (p.gerdon@ieee.org) Donald N. Heirman, Chair SC-1 Techniques and Development (d.heirman@worldnet.att.net) Dr. J.L.Norman Violette, Chair SC-2 Terms and Definitions (enviolette@msn.com) Art Wall, Chair SC-3 International Standardization (awall@fcc.gov) Daniel D. Hoolihan, Chair SC-6 Accreditation/Conformity Assessment (hoolihan@emcxpert.com) Arthur Light, Chair SC-7 Unlicensed Personal Communication Service (alight@erols.com) Daniel D. Hoolihan, Chair SC-8 Medical Device EMC Test Methods (hoolihan@emcxpert.com)
R. L. Pritchard Secretary (r.pritchard@ieee.org) Warren A. Kesselman, Treasurer/Newsletter Editor (w.kesselman@ieee.org)