Showing papers on "Electromagnetic compatibility published in 1981"

The Susceptibility of a 1K NMOS Memory to Conducted Electromagnetic Interference

Abstract: The investigation into the susceptibility of a IK bit memory as described in this paper was undertaken with the intention of gaining understanding of the nature and consequences of electromagnetic interference (EMI) on complex digital devices. The author is involved in the clearance of military aircraft for electromagnetic compatibility and this requires know­ ledge of system response to EMI. To have confidence in the hardness of an aircraft system it is necessary not only to design and build equipment capable of working in the severe electromagnetic environment encountered and created by modern military aircraft but also to be in a position to assess equipment hardness during manufacture and when installed in the aircraft.

EMC Education in an Undergraduate Cooperative Program

Abstract: Electromagnetic Compatibility (EMC) is not a c lass ica l academic subject in i t s own r ig h t , nor can i t be. In f a c t , i t i s d i f f ic u l t to define the pursuit of EMC as a separate engineering d isc ip line or a c t iv i ty because, in a broad sense, i t i s a s e l f ­ understood design objective in the development of e le c tr ic a l and e lec tron ic systems. EMC princip les are applied to a broad range of areas, such as automatic contro l, communications, power systems, computers, e tc . Achieving EMC in these areas requires an in-depth understanding of the engi­ neering d isc ip line Involved. This leads to the problem of defining "expertise" in EMC. An e lec tron ic system designer should ce r ta in ly have expertise in assuring intrasystem Electromagnetic Compatibility. He need not necessarily be an expert in such specialized areas as EMC tes ting or sophisticated EMC prediction techniques. Yet the designer should be able to e ffec t ive ly in te r ­ face with sp e c ia l is ts in these areas and to do so he should understand the fundamentals and he should be fam iliar with the EMC community and what i t has to o ffe r . EMC is a multilevel consideration. I t must be achieved in a subsystem such as a single logic gate as well as in the to ta l assembly of Individual systems. I t deals with intrasystem problems as well as in te r system problems and in a global sense spans the whole spectrum from sub-system compatibility to the to ta l ambient electromagnetic environment affec ting the to ta l conglomerate of e lec tronic support systems. This implies th a t the designer of e le c tr ic a l or e lectronic systems should have an awareness of the need fo r EMC both in terms of intrasystem EMC and in terms of compatibility with the electromagnetic environment. The topics presented in an educational program on EMC should be chosen in terms of the students ' anticipated needs and primary EMC concerns. These may range from basic EMI reduction techniques. Against th is background of ambiguity associated with the notion of EMC, the formulation of an educa­ tional program in "EMC" must be based on some ra ther a rb itra ry choices of top ics. This paper discusses possible approaches to the design of educational programs in terms of these ambiguities with special emphasis on undergraduate education. The specific format used in an undergraduate EMC course a t General Motors In s t i tu te is presented and rela ted to the needs of GM e le c tr ic a l engineers in coping with the new challenges of automotive electronic control systems Including vehicular applications of microcomputers. The involvement of a Corporate EMC committee in defining the course objectives is discussed and the behavioral objectives of the course are iden tif ied and discussed in terms of Corporate EMC objectives.

Marine electrical practice

Abstract: Insulation and temperature ratings of equipment protection and discrimination ac generators ac switchgear automatic voltage regulators dc generators dc switchgear distribution electric cables motors motor control gear semiconductors storage batteries and battery control gear lighting impresssed current cathodic protection tankers progammable electronic systems electromagnetic compatibility insulation testing.

EMC in Microelectronics a Methodology

Abstract: Limitations on present EMC approaches and a discussion of a new, probabilistic approach are given. A Compatibility Factor (C) is derived and defined. A method of applying the C at all levels in the system procurement/design cycle is given. Tools such as Output Classification Index, Fault Tree Analysis (FTA), and Electromagnetic Effects and Criticality Analysis (EMECA) are described. A brief discussion of the IAP codes' role in a probabilistic approach is given. Finally, a system compatibility flow diagram is presented, showing where these tools may be applied to.achieve compatibility as an end product.

Vehicle Testing for Electromagnetic Compatibility

Abstract: Electromagnetic compatibility (EMC) testing for the automobile has taken a new perspective in the past decade. The use of the microprocessor and integrated circuits to solve a multitude of safety, pollution, and fuel economy problems has, unfortunately, resulted in reliability problems caused by RF radiation. The success of a good EMC test capability is an understanding of the Rf radiation effects on the automobile and the electronic equipment required to simulate a wide range of radiated environments.

Nonlinear Effects Models for the Intrasystem Electromagnetic Compatibility Analysis Program (IEMCAP)

Abstract: A number of important sources of EMI problems such as desensitization, intermodulation, crossmodu­ lation and spurious responses result from nonlinear operation of circuits. This paper describes mathe­ matical models which will be used to expand the capabilities of the Intrasystem Electromagnetic Compatibility Analysis Program (IEMCAP) to include prediction of possible interference situations due to these equipment nonlinear effects. These models are based on a modified nonlinear transfer function approach which produces degradation criteria (Inter­ ference Margins) which are consistent with the present IEMCAP philosophy.

Electromagnetic interference assessment of an ion drive electric propulsion system

Abstract: An electric propulsion thrust system has the capability of providing a high specific impulse for long duration scientific missions in space. The EMI from the elements of an ion engine was characterized. The compatibility of ion drive electric propulsion systems with typical interplanetary spacecraft engineering was predicted.

New Port Spectra and Nonaverage Power Receptor Models for the Intrasystem Electromagnetic Compatibility Analysis Program (IEMCAP)

Abstract: This paper describes the new port spectra and nonaverage power receptor models developed for the Intrasystem Electromagnetic Compatibility Analysis Program (IEMCAP). The new port spectra model re­ places the "quantization" method for modeling a port's spectra. This new model automatically gen­ erates the equipment frequency table, and the cor­ responding port frequency amplitudes for all the prestored emitter and receptor models as directed by the user's values for the input parameters re­ quired by IEMCAP. The new receptor model provides the capability of determining the EMC for devices in a system whose degradation is a function of the waveform rise time, energy, peak current or peak voltage. These new receptor models are applicable for both deterministic and stochastic signals.

The electric and magnetic response of a system in an external electromagnetic field

Abstract: We propose a novel way of identifying the electric and magnetic response of a system in an external electromagnetic field, illustrating in particular with the current density response.

EMC Education - the Missing Link

Abstract: This paper is an introduction to the session on EMC Education which is being spon­ sored by the EMC Society Education Committee. The paper discusses the need for EMC educa­ tion and provides an overview of the various educational opportunities available, as well as serving as an introduction to other papers in the session.

Composite Material Aircraft Electromagnetic Properties and Design Guidelines

Abstract: : This document collects and primarily summarizes aircraft advanced composite material electromagnetic properties, and secondarily, summarizes composite material mechanical, thermal, environmental, fabrication properties noting their ramifications on electromagnetic performance. It, then, overviews the electromagnetic sub-disciplines of threats, external to internal aircraft coupling, component and subsystems susceptibility protective methods as well as test and evaluation of small sample to total aircraft composite material electromagnetic performance. The sub-disciplines constitute a partioned set of independent variables which allow the reader to locate his area of interest in one section of the book. The sub-discipline are then combined to perform total aircraft electromagnetic system performance noting the protective methods, advantages and penalties.

A Simplified Method for Obtaining the Taylor-Fourier Series Coefficients of a Single Diode Mixer

Abstract: An approximate method is presented for obtaining the Taylor-Fourier series coefficients that can be used to model the intermodulation and spurious responses of a single diode mixer. This method makes use of simplifying assumptions to obtain estimates of many of the coefficients given any one of them. The procedure is applied to a single diode mixer, and the results are compared to a more rigorous analysis method which has compared well with measured data. INTRODUCTION At the 1977 IEEE EMC Symposium, a method was presented for estimating mixer intermodulation (IM) and spurious (SR) response levels.1 The levels were shown to be proportional to the coefficients of the Taylor-Fourier series expansion of the mixer output current equation. The paper contained a procedure for obtaining the Taylor-Fourier coefficients that required several static diode and circuit parameters. However, the EMC analyst usually has access only to the mixer conversion efficiency, and either the 1 dB gain compression or third order IM intercept point. From this data, one can estimate values of certain Taylor-Fourier coefficients for that mixer. If a simple relationship between coefficient’s were found this limited data might be sufficient for modelling purposes. The graph in Figure 1 represents a typical spurious response matrix for a mixer. Shown are measured data and response levels calculated from the method in Reference 1• The measured data were obtained by setting the RF signal generator at each spurious response frequency, then adjusting the signal level until the standard IF response was achieved, e.g., 10 dB above the noise level. The input level is recorded. Sometimes the matrix is normalized to the level for the P = 1, Q — 1 response. The data of Figure 1 show some interesting features which are common to wide-band mixers. First, one could draw an envelope for the Q = 1 responses which decreases at a rate of 1/P, or -20 log P in dB. Second, the Q >_ 2 responses are relatively independent of P. This is shown to be expected using . a generalized Taylor-Fourier series analysis of mixers• These results may be seen from an examination of the current-voltage transfer characteristic of the single-ended diode mixer shown in Figure 2. Think of the local oscillator (LO) as a switching signal. When the LG signal is a positive peak, the RF signal is passed with full transconductance. When at a negative peak, there is no significant current. Thus, pulses of the RF signal are permitted at a repetition rate equal to the LO frequency. The spectral energy is distributed in lines (delta functions) at frequencies IfRF±PfL0|. Furthermore, since the pulses have a relatively high duty cycle, the envelopes of the amplitudes of these lines decrease according to ^ (i.e., * spectrum). We will name these Q = 1 responses. In addition, as the LO signal crosses the nonlinear region, harmonics of the RF signal are produced in a similar manner. These are relatively short pulses whose peak amplitudes and widths depend on the peak mixer nonlinear conversion efficiency and the LO signal amplitude. For example, pulses at 2 fRF also occur at the repetition rate of fL0* (This is equivalent to saying that the second order Taylor series coefficient is a time-periodic pulse train)• The spectral energy of these pulses is distributed in lines at )fRF±PfLQ|. Since the duty cycle is relatively low, many of these lines (for small P values) will have approximately equal amplitude.a We will call these Q = 2 responses. Once realizing the aforementioned independence of P, the problem reduces to finding simple relationships for the response separations with Q. This is done in the following derivation for a single ended diode mixer, where the separation is determined between the Q = 1 and Q = n coefficients: the P = 0, Q = 1, and P = 0, Q = n coefficients, and a0 n̂ . DERIVATION We begin by representing the mixer transfer characteristics by a Taylor series: 1 = § V r f Q <1)

EMC Language in Perspective

Abstract: It is quite probable that most of the EMC termin­ ology was initially coined in a logical and descriptive manner. It is now apparent that many of the terms have evolved into meanings not intended, thus, the language has become typecast into a jargon not easily explained to the nonparticipants. This situation, unfortunately, leads to the invention of new terms. Whether or not the trend can be reversed is debatable. This paper discusses the possible discrepancies and proposes alternatives to conform to a self descriptive language.

Analysis of Interference Caused by the Solar Power Satellite to Satellite Earth Terminals

Abstract: The solar power satellite (SPS) is a concept for generating electrical power from solar energy via a geosynchronous orbiting satellite. A facility, such as this, would be able to send approximately 5 to 10 gigawatts of power to earth on a highly focused 2450 MHz microwave beam. The electromagnetic compatibility problems cause by this amount of microwave power transmission are recognized as a critical factor in the implementation of such a system. This report examines the potential for interference between SPS and conventional satellite earth terminals. The report begins with a general discussion of the different ways that interference between SPS and satellite systems can occur. Estimates are made of the levels of harmonics and out-of-band noise that are likely to be radiated by SPS. These levels are then compared to the interference threshold for various representative satellite scenarios. The report concludes that a potential for interference exists in the 2500 MHz to 2690 MHz direct broadcast satellite frequency assignments. Another potential problem is SPS radiation at the 7350 MHz 3d harmonic that falls within the 7300 MHz to 7400 MHz space-to-earth government satellite band.

Evaluation of the Electromagnetic Compatibility (EMC) of Tactical Communications Nets

Abstract: Evaluation of tactical deployments, from an EMC standpoint, involves the basic question; "To what extent will the capabilities (or performance) of a deployed force be degraded because of unintentional interference?" A host of complexities arise in arriving at answers which are technically sound and, of major significance, answers which are understandable and meaningful to the developers of military tactical doctrine.

The role of an electromagnetic environment model in spectrum management

Abstract: The role of an electromagnetic (EM) environment model is spectrum management is developed. Spectrum management is traced from electromagnetic compatibility (EMC) considerations in international agreements through related domestic law to the fundamental spectrum management procedures -- allocation, allotment, and assignment. The need for a model of the EM environment is derived from requirements of allocation, allotment, and assignment proceedings. Data elements required to support an EM environment model for spectrum management purposes are reviewed. An outline and derivation of a general EM environment model is given. The ways systems respond to the EM environment are cataloged and reviewed so that specific applications of an EM environment model are readily apparent. Applications and limitations of current models are discussed.

Electromagnetic Compatibility Analysis for a Satellite Power System Receivlnq Site in the Mojave Desert

Abstract: The Department of Energy (DOE), along with the National Aeronautics and Space Administration (NASA), has been evaluating the Satellite Power System (SPS) as a source of baseline electrical power The objective of the SPS program is to develop an initial understanding of the technical feasibility, the economic practicality, and the social and environmental acceptability of the SPS concept One of the potential problems identified early in the concept analysis was the electromagnetic compatibility (EMC) of an SPS with existing and planned electromagnetic and electronic systems A preliminary study has been conducted to show the EMe problems for an initial candidate receiving antenna (rectenna) site in the Mojave Desert of California Amethodology has been developed and demonstrated for rectenna site EMC analysis and impact evaluation For the particular site chosen, the majority of the severe impact interference problems concerned military operations The systems degraded by SPS off-site microwave beam components were integral systems and subsystems of complex Development and Operational Test and Evaluation programs Based on the operational system degradations near the Mojave site and the inability to establish mitigating strategies without unacceptable operational compromise, a second site north and east of the original was proposed

Propagation of an electromagnetic wave in a coaxial cable. The case of a narrow gap

Abstract: A study is made of the propagation of a discontinuity of the electromagnetic field in a magnet in a coaxial cable. The shape of a discontinuity of the electromagnetic field propagating along a magnet from a voltage source is found. Under the assumption of a small gap between coaxial, infinitely conducting cylinders, the field parameters behind the discontinuity are determined.

The role of an electromagnetic environment model in spectrum management

Abstract: The role of an electromagnetic (EM) environment model is spectrum management is developed. Spectrum management is traced from electromagnetic compatibility (EMC) considerations in international agreements through related domestic law to the fundamental spectrum management procedures -- allocation, allotment, and assignment. The need for a model of the EM environment is derived from requirements of allocation, allotment, and assignment proceedings. Data elements required to support an EM environment model for spectrum management purposes are reviewed. An outline and derivation of a general EM environment model is given. The ways systems respond to the EM environment are cataloged and reviewed so that specific applications of an EM environment model are readily apparent. Applications and limitations of current models are discussed.

Implementation of EMC Testing of Automotive Vehicles

Abstract: A complete facility to assure electromagnetic compatibility of automotive vehicles has been implemented. This facility includes automated shielded anechoic rooms equipped with program controlled dynamometers for radiated susceptibility and radio compatibility testing, computer controlled transient measurement and conducted susceptibility laboratory, open-air sites for narrow and broadband radiated emissions and mobile equipment for onboard vehicle testing. This paper presents the procedures and methods performed in the planning, construction and validation of the facility. Value analysis, system development and implementation results will be detailed.

General Considerations In Attempting To Characterize Non-uniform, Non-planar Electromagnetic Field Environments

Abstract: Power density and electric field strength are often used almost interchangeably to describe t he intensity of an electromagnetic environment. However, the simple relationship (PD=E /377) between them is invalidated if the field is non-uniform and non-planar. Consequently, a more complex definition of power density is required. This paper discusses expanded definitions of power density in terms of rms electric and/or magnetic field strengths. Measurements of electric and magnetic fields demonstrating the relationships of these various definitions and their range of applicability and usefulness are presented and discussed. Recommendations concerning the acceptance of these proposed definitions in electromagnetic hazards work are proferred. 2