A MESSAGE FROM YOUR CHAIRMAN:WHERE DO WE GO FROM HERE?

D. R. J. WHITE

As your new PTGEMC Chairman, I should liketo do a little introspection at this time. Thus,let's reidentify our needs and objectives, indicatewhat may be done to fill these needs and suggest afew ways and means. I shall touch upon only a fewrepresentative situations to get you thinking.

First, the EMC Community needs a good shotin the arm of a quantitativeness type of adrenalin.It is often said that marketing types "name drop"in order to make an impression regarding theircontacts. The EMC technological community alsoname drops in a different sense. Here are a fewexamples: What does compatibility really mean,that is quantitatively? What are the EMC per-formance acceptability criteria? What is the dif-ference between susceptibility and vulnerability?What does a valid RFI prediction model mean?What does an equipotential plane or grid reallymean? What does a five to one length-to-widthratio of a bond mean? How do we measure itsimpedance at 1 gc? Do we really have to meas-ure it at 1 gc anyway? What does optimize mean?What are the variables, parameters and criteria ofoptimization? And, so it goes, that if we are notmore careful, the technological profession willbecome another hypocrisy of our time.

Why do we need more meaningful electro-magnetic compatibility criteria? Generally, weare so busily engaged in developing things anddelivering output that little time for ponderingsomething as fundamental as requirements seemsto remain. The subject of interference standardsand specifications, for example, has been undercriticism for a long time. There exist many ap-plications where RFI specifications are too strin-gent, where they need tightening, and where thereexist complete voids. Thus fresh thinking and amajor overhaul are needed now.

There exists very little system effectivenesscriteria for EMC, notwithstanding effort expendedin the analysis of communications-electronic(C-E) systems, and other efforts to enhance per-formance or to conserve or reduce contaminationof the frequency spectrum. The EMC Communityhas almost no measures of scoring RFI damage interms of effectiveness criteria and performancerequirements for systems or equipments inachieving their missions. This involves uservalue judgments of such things as acceptibilityscores for weapon kill probability, message errorrates, flexibility reduction and cost implications.Minimizing the number of RFI aborted messages,for example, is meaningless unless redundancy,logistics, security or cost impact is considered.

Regarding the subject of mathematical modelingand computer simulation of EMC situations, it isregarded fashionable to be in this business. Thepurported advantages are almost completelyshrouding the facts. One disappointment here in-volves the lack of gainful use of these tools espe-cially where multi-C-E systems are involved.For example, how is digital computer simulationused to determine effectiveness of a Battle Groupor an Air Defense Sector in which EMC is only oneconsideration? What about tie-in with EMW,reliability and mission success? Where is themodeling of the behavior of the human element?There exists little value in having libraries ofC-E characteristics and electromagnetic scenariosif we do not have either 'optimization' or effec-tiveness criteria reasonably well defined.

On the subject of EM environmental simulators,especially where EMC vulnerability testing isimplied, one approach is latent to the idea ofcalling them evaluators. If performance criteria

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of representative equipment were established atthe beginning, then one could back into the simu-lator problem by translating these criteria intoparameters to be measured, generation functionsrequired and their allowable variations or errors.Simulator characteristics could then be estab-lished together with cost for physical realization.Finally, a yield-cost ratio analysis would suggestwhere reasonable tradeoffs may exist for differentapplications. Unfortunately, the route followedinvolves such things, for example, as the perennialbattle between stochastic and discrete simulationand RF vs video injection, because technologistsare trying to define what the simulator character-istics should be without a realistic measure ofwhat they are to accomplish.

On the subject of EMC instrumentation, it isapparent that equipment used by the EMC Com-munity today is not significantly different fromthat used nearly ten years ago, notwithstanding theimproved creature comforts which have been addedand the extended frequency coverage. For themost part, sensitivities are clearly inadequate byat least 20 db and bandwidth choice is limited formany applications. The prime method of record-ing and documenting hard copy data is still prin-cipally the point-by-point meter reading method.Further, EMC instruments are not designed forstatistical recording of data despite the need.

Perhaps the greatest offender of the instru-mentation problem has to do with the methods ofusing existing instruments, viz, design-of-experiments. For example, the methods ofmeasuring attenuation of shielded enclosures,whether a small room or building, generallymake little sense because of large signal varia-tions which result inside an enclosure whenilluminated from the outside. Thus it is apparentthat a statistical documentation of the trans-missivity in terms of, say, its mean value andthe 1 per cent or 99 per cent variance pointswould more meaningfully describe the perform-ance at a given frequency.

Another example of measurement misuseinvolves the method of documenting electromag-netic environments at sites where the suitablenessfor radar or communications equipment locationis to be determined. Here again, the statisticalnature of the number of radiators on the air at anyone time, the scintillation of some radiators dueto antenna scanning effects, the time of day,weather or propagations conditions and other con-

siderations require defining meaningful criteriaand standards.

Regarding the subject of education and trainingsubstantial opportunities exist. For example,

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while we conduct our own EMC symposia where weenjoy a certain amount of technological inter-change, we are not cross pollinating with othersoutside the EMC Community. Here, the presenta-tion of EMC papers at non EMC symposia wouldstress the tutorial flavor since it is basicallyeducation that is sought. The purpose of sucha program is to inject the EMC impact and under-standing into other disciplines involving design,development, fabrication, installation, operation,maintenance and retrofit of systems or equipmentsat all levels.

Finally, it is apparent that improvement isrequired in the area of components and materials.One example of this includes developing tubes andtransistors which have greater linearity over adefined dynamic range in order to minimize pro-pensity to intermodulation and harmonics. Anotherexample involves the development of electronicallytunable inductors and capacitors having Q factorsin order that tuned-radio-frequency receiversmay be more fully developed for relieving thetired and susceptible superheterodyne receiver.Another way of achieving higher component Qfactors involves cryogenic techniques.

Return to the subject of where does yourPTGEMC fit into the above and related needs, wesummarize:

1) Transactions on EMC are prepared and dis-tributed about three times a year amongstmore than 1200 PTGEMC members.

2) PTGEMC participates in or supports threeplatforms each year where EMC papers arecollectively presented at annual symposia.

3) Five or six times a year PTGEMC dis-tributes its Newsletter to its members.This contains information of currentinterest with regard to EMC and relatedactivities.

4) Section chapters have been formed in sev-eral cities to provide a forum for localEMC members to meet and exchange ideasor hear a guest speaker.

The conduct of these and other activities isdirected or coordinated by your PTGEMC Ad-ministrative Committee consisting of fifteen mem-bers, most of whom are chairman on subcommittees

The conduct of these and other activities isdirected or coordinated by your PTGEMCAdministrative Committee consisting of fifteenmembers, most of whom are chairman on sub-com;n'ittees. These subcommittees cover such

matters as the designation of annual awards,overseeing and coordinating the activities of theEMC chapters, the continuing examination andupdating of the constitution and bylaws ofPTGEMC and the pursuit of new members.Another committee involves technical papers andis responsible for soliciting, reviewing and select-ing them. A different committee makes the ar-rangements for publishing these papers in theTRANSACTIONS.

The EMC Conference committee is involved inthree annual symposia. The extra-EMC Confer-ence Committee encourages and, where necessary,prods PTGEMC members to present technicalpapers outside the EMC Community. The Tech-nical Advisory Committee will become especiallyactive this year in standards and terminology. Itwill work or conduct information exchange withrelated committees inside the IEEE and outside

organizations such as the EIA M-5.8 Committee onRFI. Another committee pertains to the IEEEAreas of Activity resulting from the merger of theInstitute of Radio Engineers and the AmericanInstitute of Electrical Engineers.

One of the biggest responsibilities entrusted tome during my tenure of office this year is to makesure that all these efforts are being directed to-ward purposeful and gainful ends. This is espe-cially important in our Occidental way of lifetoday, because we are all very busy about ourother businesses. Thus, since time is a pre-mium, it is important that whatever we do we geta high yield for our investment. Toward this end,I invite each of you to personally write me andgive me your thoughts regarding how we mightdirect PTGEMC efforts within the confines of ourconstitution and resources.

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