1、EIA BULLETIN Historical Rationale for Military EM1 Limits JANUARY 1993 ELECTRONIC INDUSTRIES ASSOCIATION UA ELECTROMAGNETIC COMPATIBILITY BUUETIN NO. EMCB 1-1 HISTORICAL RATIONAL FOR MILITARY EM1 LIMITS PREPARED BY G-46 ELECTROMAGNETIC COMPATIBIUTY COMMlTEE TASK REFOnT 069 EECTRONIC INDUSTRIES ASSOC
2、IATION ENGINEERING DEPARTMENT mi PENNSnVANIA AVE, N.W. WA$HIWG?ON, BC 2OO6-1813 Acknowledgement This EIA Bulletin No. EMCB1-1, Historical Rationale for Military EM1 Limits, is presented by the Electronic Industries Association G46 Electromagnetic Compatibility Committee. It has been prepared to prov
3、ide a reference source for electromagnetic compatibility practitioners to enable more knowledgeable application of MI requirements in equipment and system specifications and designs. Appreciation is extended to Ken Javor, principal author David Cofield, U.S. Army Communications Electronics Command;
4、Al Parker, Solar Electronics Company; and John Zentner, U.S. Air Force Aeronautical Systems Division for their valuable assistance. A special acknowledgement goes to Mr. Kent Mills, KMX Corporation for formatting the dowment for publication. The G46 Committee will continue to devote its efforts to t
5、he advancement of the knowledge and understanding of the subjects of electromagnetic environmental . effects. Therefore, we invite your comments on this publication and welcome your suggestions concerning publication of additional information that would aid in the effective conduct of any activity r
6、elative to training and education within the electromagnetic environmental effects disciplines. The appearance of a reference in this Bulletin does not necessarily imply endorsement by the EIA NOTICE EIA Engineering Standards and Publications are designed to serve the public interest through elimina
7、ting misunderstandings between manufacturers and purchasers, facilitating interchangeability and improvement of products, and assisting the purchaser in selecting and obtaining with minimum delay the proper product for his particular need. Existence of such Standards and Publications shall not in an
8、y respect preclude any member or nonmember of EIA from manufacturing or selling products not conforming to such Standards and Publications, nor shall the existence of such Standards and Publications preclude their voluntary use by those other than EIA members, whether the standard is to be used eith
9、er domestically or internationally. Recommended Standards and Publications are adopted by EIA in accordance with the American National Standards Institute (ANSI) patent policy. By such action, EIA does not assume any liability to any patent owner, nor does it assume any obligation whatever to partie
10、s adopting the Recommended Standard or Publication. Technical Bulletins are distinguished from EIA Recommended Standards or Interim Standards, in that they contain a compilation of engineering data or information useful to the technical community, and represent approaches to good engineering practic
11、es that are suggested by the formulating committee. This Bulletin is not intended to preclude or discourage other approaches that similarly represent good engineering practice, or that may be acceptable to, or have been accepted by, appropriate bodies. Parties who wish to bring other approaches to t
12、he attention of the formulating committee to be considered for inclusion in future revisions of this Bulletin are encouraged to do so. It is the intention of the formulating committee to revise and update this ,Bulletin from time to time as may be occasioned by changes in technology, industry practi
13、ce, or government regulations, or for other appropriate reasons. Published by ELECTRONIC INDUSTRIES ASSOCIATION Engineering Department 2001 Pennsylvania Ave., N.W. Washington, D.C. 20006 PRICE: Please refer to the current or call Global Engineering Document8, USA and Canada (1-800-854- International
14、 (714-261-1455) Catalog of EIA C JEDEC ITANDARDS L EIGINEERI#Q PUBLICATION8 7179) , Copyright 1993 All Rights Reserved Printed in U.S.A. EIA G-46 PANEL TASK 069 REPORT: HISTORICAL RATIONALE FOR MILITARY EM1 LIMfTS PREFACE Almost fifty years have passed since the advent of formalized military specifi
15、cations requiring EM1 qualification of electricailelectronic equipment. From a few specialized emissions measurements an entire industry has grown up. In the nature of such an evolution the limits and procedures have hecome codified and passed on from program to program. The form has been kept, but
16、in many cases the functionality has been lost. Some of the most basic limits and methods are largely proof of compliance requirements, with a sometimes questionable relationship to system level EMC concerns. This was recognized as long ago as 1967. The top level EMC specification, MIL-E-605 ID, EMC
17、Requirements, System (still current at this writingj stated, “3.2.4.1 Suhsvste mdeuiiinments. Unless otherwise specified in the contract, sub- systemdquipments shrill he designed to meet the requirements of MI1-STD-461 and MIL-STD-462. Since SOI of the limits in these standards are very severe, rhe
18、impact of these limits on system effectiveness, cost, and weight shall be considered Proposed modifications to the limits shall be included in the EMC plans for the system and su bsystemdequi pments .” (Au thors italics) i The purpose of this document is to foster an engineering issues oriented unde
19、rstanding of military EM1 requirements. There are several reasons that this is important. The MIL-STD-461D and MIL-STD-462A revision process is currently nearing completion, There is little understanding of how the current (MIL- STD-46 i C) requirements came about. MIL-STD-46 1 D promises to be in s
20、ome cases a radical departure from the past, but in others cases quite traditional. The MIL-PRIME philosophy being incorporated into a new system level elecuomagnctics effects standard will place a premium on the understanding of engineering issues behind EMUEMC requirements. Imposition of MIL-STD-4
21、6 1 requirements in the past has placed the responsibility for EMC design on the Procuring Activity. Suppose a weapon system were to have a system level incompatibility due to MIL-STD-461 compliant equipment interaction. Given a reasonable configuration equipment installation, the contractor could m
22、ake a case requiring the Procuring Activity to pay for the fix. Under MIL-Prime philosophy, the contractor will achieve system level EMC in part by sysrem application speciflc tailoring of MIL-STD-461 requirements. Such tailoring will become a more visihle responsibility of the contractor. 2 There i
23、s thus a need for a broader understanding of the enpinering issues behind EM1 requirements. Rationale for the limits and test procedures are unknown to the majority of industrys EMC engineers. Review of specifications and papers written in the formative years of the discipline reveals strong interes
24、t in the design of limits and procedures. There has been a shift away from this aspect of EM1 control towards a design to specification compliance emphasis. Optimum techniques for designing to compli- ance are very important. However, if the EM1 limitslprocedures are themselves not optimized, then t
25、he best the cleverest designer can hope to achieve is to minimize the cost, space, and weight impact of the improper requirement. The EMC discipline is extremely empirical in nature. In general, the control of I EIA G-46 PANEL TASK 069 REPORT HISTORICAL RATIONALE FOR MILITARY EM1 UMCTC EM1 has been
26、preceded by an EMIincident. The problem is recognized, diagnosed, and fixed. Then, with hindsight, controls are instituted to prevent reoccurrence. A statement of general validity concerning military EM1 performance requirements is that they are artifacts of a particular solution to a specific histo
27、rical problem. In some cases, the historical problem is gone but the controls remain. Several valuable efforts along the linesof thisdocument have been previously rendered by C.B. Pearlston (1967). Al Parker (1990) and Dave Cofield (199 1). The Pearlston report compares and contrasts EM1 , specifica
28、tions of the day. Mr. Parker, a key supplier of EM1 test equipment and a pillar of the industry since the 50s. delivered his historical perspective at an IEEE EMC chapter meeting. These reports are both included as appendices to this document. Mr. Cofields informative history “Fifty Years of EMC in
29、the Army”isavailab1e for all to read in the 1990 InterferenceTechnology Engineering Master - ITEM. Mr. Cofield has been active in Army EMC since the early days of MIL-STD-461A. and is a member of the Tri-Service committee revising MIL-STD-461/462. When MIL-STD-46 1D and MIL-STD-462A are released, th
30、ey will contain appendices with the rationale behind each requirement and test method, as well as suggestions for appropriate tailoring. Present EM1 limits and test methods have evolved from earlier specifications. These are listed and discussed. Many of the limits and methods derived in the 1950s a
31、re no longer applicable to todays technology and should be replaced. Suggested changes are listed for emission and susceptibility considerations, and alternative methodologies are discussed. ii EIA E46 PANEL TASK O69 REPORT: HISTORICAL RATKlNALE FOR MILITARY EMI UMKS TABLE OF CONTENTS Preface Introd
32、uction 1 Some Milestone Specifications . 1 JAN-1-225 and MIL-1-6 18 1 . The Beginning . 2 MIL-I-6181B (and NADC-EL-5515) 2 MIL-STD-826: An Attempt at a Tri-Service Standard 2 MIL-STD-461, MIL-STD-462: The Tri-Service Standard . 3 Issues . 4 . NanowbandBroadhand: An Important Distinction Obscured by
33、Automated Test Procedures . 4 Technical Rationale for Conducted EM1 Requirements . 7 Discussion of Voltage Ripple 7 Bus Resistive Frequency Range 7 Bus Inductive Frequency Range . 7 The Power Bus as Transmission Line . 8 Discussion of Electric Field Radiation from the Power Bus . 9 Discussion of Str
34、ucture Currents (Vehicle Skin Protection) . 10 Source Impedance Standardization for CE Current Tests . 10 Source Impedance Standardization for CE Voltage Tests 11 Conduction Modes: Common Mode and Differential Mode . 11 CE Measurement Procedures 10 Single Phase Differential Mode 11 Single Phase Comm
35、on Mode 12 Conduction Mode Isolation . 13 Test Methods . 13 Historical Military Conducted EM1 Control . 14 Structure Current Return vs . Above Ground Current Return 15 Transient Conducted Emissions 18 Low Frequency Conducted Emissions 20 Signal Line Conducted Emissions . 22 Audio Frequency Conducted
36、 Susceptibility 23 RF Conducted Susceptibility . 23 Authors Calculation of BCI Current for CS 10 26 Technical Rationale for Radiated EM1 Measurements . 26 Historical Military Radiated EM1 Requirements 31 Radiated Electric Field Emissions . 32 Radiated Magnetic Field Emissions 37 REOl/RSOl 38 REO4 40
37、 Radiated Susceptibility 42 . EIA 646 PANEL TASK o69 REPORT: HISTORICAL RATIONALE FOR MILITARY EM1 UMS Conclusion . 44 References . 47 Lngineering vs. Specmanship. 45 Appendices Appendix A: Appendix B: Appendix C: Appendix D: Appendix E: Appendix F: Parker, A. T. “A Brief History of EM1 Specificatio
38、ns” (1992) . Al Air Force Report No. SSD-TR-67- 127 “Historical Analysis of Electro-magnetic Interference Limits” by C. B. Pearlston, Jr. (1967) . B 1 NADC-EL-55 15 “Final Report, Evaluation of Radio Interference Pickup Devices and Explanation of the Methods and Limits of Specification No. MIL-I-618
39、1B” Cl Important and Hard To Find EM1 Specifications JAN-1-225 Dl AN-1-40 . D2 MIL-1-61 8 1 D3 MIL-I-6181B . D4 CE07 (Load Induced Transient) Test Procedure . El Modified RS02 Test Procedure . FI N - EIA G-46 PANEL TASK O69 REPORT: HISTORICAL RATIONALE FOR MILITARY EM1 UMITS INTRODUCTION The EM1 con
40、trol program exists like an insurance policy, to replace unknown (and potentially large) program performance, schedule and budget im- pacts with a predictable level of effort which may be factored into the cost and schedule of the program. It is a continuing responsibility to en- sure that the premi
41、ums reflect the value of the insured item and the risks involved. This docu- ment looks at what it takes to insure EMC consid- Some Miles tone Specifications This section traces the technical evolution of Air Force specifications. The author, whose back- ground is aerospace, would like this section
42、to be inclusive of all Service specifications. At the present time, this has not been possible. Readers of this document With pertinent information to share are asked to communicate with the author eringelectromagneticspectrum usage in the 1990s. via ihe EIA G-46 committee. - vs. current EM1 control
43、 techniques. It will be shown that the conducted emissionslsusceptibility limits and test methods overlook some very important factors and that the low frequency radiated (emission) limit and test method (emission/ sus- ceptibility) is quite dated. A condensed and abridged gene- alogy of military EM
44、I/EMC speci- ficationsand standards is presented in Figure 1. The phrase “E pluribus unum” is as good a description of the evolution of EM1 standards as it is of United States history. What is important to understand is, as usual, the reasons behind the stan- dards and their evolution, rather than t
45、he names -d dates. Never- theless, a knowledge of the stan- dards. their evolution and the time frame is useful. An excellent source is in Volume 1 of the older (197 1) Don WhiteEMC handbook senes, pages 4.13ff. (31 Figwe 1: Abhrcviated genealogy of military EMI specifications and standards AF-AkFor
46、ceN-Navy A-Anwj Cc-CigiaiCaps I945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1 EIA G46 PANEL TASK 069 REPORT: HISTORICAL RATIONALE FOR MILITARY EM1 UMITS JAN-1-225 and MIL-1-6181 The Beginning 4 JAN-1-225 was a test method for measurement of RF conducted and radiated noise from 150 kHz to 20 MHz.
47、 The source impedance for conducted emission measurement purposes used 8 pF ca- pacitance from the power feeder to ground to bypass the power supply, and 10 leads from the capacitors to the measurement point. The Ferris noise meter type 32B was specified. The RF input was twinaxial, as opposed to to
48、days single ended coax inputs. Such an input would have had a higher resistance than 50 . A 10 pF blocking capacitor was used to isolate the receiver input from the power source, and convert the required 24” twisted pair receiver input to coax, for the purpose of minimizing stray pickup. This tech-
49、nique was adopted for MIL-1-6181. Radiated measurements require use of the 41” rod. Shield rooms were homemade at that time, and instruc- tions are included in the case of broadcast recep- tion to tune to another nearby frequency. No limits are included in JAN-1-225. The original concept was to put limits in equipment procure- ment specifications. Note: This specification was for general aircraft, but it antedates the creation of the Air Force from the WWII era Army Air Force. Hence the specification designation Joint Army- Navy (JAN). CE and RE limits in MIL-1
