Showing papers on "Electromagnetic compatibility published in 1976"

Noise Reduction Techniques in Electronic Systems

Abstract: This updated and expanded version of the very successful first edition offers new chapters on controlling the emission from electronic systems, especially digital systems, and on low-cost techniques for providing electromagnetic compatibility (EMC) for consumer products sold in a competitive market There is also a new chapter on the susceptibility of electronic systems to electrostatic discharge There is more material on FCC regulations, digital circuit noise and layout, and digital circuit radiation Virtually all the material in the first edition has been retained Contains a new appendix on FCC EMC test procedures

Transmission line fields

Abstract: Calculated and measured transmission line electrostatic and electromagnetic fields are presented. The 30 line rotating E and B vectors are presented as vector loci and the phasor space potentials are presented as mappings. Lateral profiles of ground level electrostatic and electromagnetic fields are calculated and compared to measured values.

Ball lightning as electromagnetic energy

Abstract: NONE of the theories1–8 proposed to explain ball lightning seems able to account satisfactorily for the experimental evidence9–14. Jennison15 has suggested that ball lightning is a spherical stable standing wave of electromagnetic radiation. The proposal that ball lightning in effect consists of electromagnetic field energy trapped in an evacuated cavity of approximately spherical shape, with an ionised sheath separating it from the atmosphere, merits further examination.

The transient magnetization process and operations in the plunger type electromagnet

Abstract: D.C. electromagnets are generally used in electric devices such as an electromagnetic switch, an electro-magnetic relay, an electromagnetic value, etc.. The transient magnetization affects the determination of the electromagnetic force and the performance characteristic. However, there are few reports on the details of the transient phenomena in an electromagnet. The purpose of this paper is to describe two phenomena which are obtained from the numerical analyses and some experiments. One is the time lag of magnetic flux due to the skin effect. The other is the transient magnetization process near the gap in the plunger type electromagnet made of solid core.

Improvement of EMC by Applying Ambiguity and Environmental Diagrams to the Design of Radar Waveforms

Abstract: A technique for improving the electromagnetic compatibility of a radar system with respect to its operating electromagnetic environment and to assess RF spectrum usage is presented. The technique involves the use of the ambiguity diagram derived from the waveform and the construction of environinental diagrams for the radar. Overlays of the ambiguity diagram upon the environmental diagram, along desired target trajectories, provide a pictorial view by which EMC analysis and spectrum usage can be interpreted. The technique lends itself to the early phases in radar concept or development where waveform design can be modified. The technique also lends itself to assessing design towards receiver interference rejection. Only nominal system parameter data is required for implementation.

A Technology Plan for Electromagnetic Characteristics of Advanced Composites.

Abstract: : The report presents a program for the development of the fundamental technology for the assessment of the electromagnetic compatibility (EMC) effects of the use of advanced composite materials in aircraft. A survey of the electromagnetic impact of the use of advanced composite materials in aircraft is given. Electromagnetic hazards (lightning, nuclear blast EMP, precipitation static and radar) are described and related to the shielding performance of advanced composite materials. In addition the effects of composite materials on antenna performance is discussed. The measurement of basic electrical properties and the definition and measurement of shielding effectiveness is treated in detail. Finally and most importantly, future study tasks are defined which aim to develop electromagnetic environment analysis capability for existing and future aircraft systems using advanced composite materials. (Author)

Improved Techniques and Instrumentation for EMC Measurements

Abstract: This paper presents a survey of improved measurement techniques, instrumentation, and data presentation for accurate, meaningful evaluation of electromagnetic compatibility (EMC) of electronic systems and sub­ systems. These techniques and instrumentation were developed as alternatives to conventional, MIL-STD461/462, measurements which recommend screen room testing with conventional antennas. These alterna­ tives are used to accurately measure and quantify EM emissions from electronic equipment and/or for estab­ lishing standardized EM susceptibility test fields. Dramatic improvement (worst case errors of 1 to 3 dB compared with 40 dB from conventional screen room measurements) have been demonstrated. The techniques described in the paper include: 1) low-Q or under­ ground enclosures, 2) mode stirred, shielded enclo­ sures, 3) specially designed, shielded, transverse electromagnetic (TEM) cells, 4) broadband field probes capable of measuring complex average or peak fields without causing perturbation, and 5) time and ampli­ tude statistics for characterizing the measured data.

Evaluation of In Vivo Versus In Vitro Test Methods for the Determination of Electromagnetic Compatibility of Implantable Cardiac Pacemakers at 450 MHz

Abstract: This study evaluates two systems for measuring the susceptibility to EMI of implant­ able cardiac pacemakers. Each system consist­ ed of four parts: the pacemaker; a 450 MHz electromagnetic field; the instrumentation for monitoring pacemaker function; and the medium in which the pacemaker is placed for test. The two systems differed in the medium used; one was an empirically derived solution and the second was a canine.

A Model to Predict Mutual Interference Effects on an Airframe.

Abstract: : Sponsored by the FAA, the Electromagnetic Compatibility Analysis Center has developed an analysis model, called AVPAK, to determine the mutual interference effects of introducing new avionics equipment to an existing airframe containing operational equipment. The model has been updated, improved, and expanded in a series of scheduled efforts. In this report, those improvements have been summarized and the current version of the model (AVPAK 3) is completely documented. (Author)

Electromagnetic Field, in a High Frequency Range, of High-Voltage Transmission Lines and Its Effects on the Response of a Terminated One-Wire Transmission Line Set Near the Ground

Abstract: In this paper we shall present two useful calculations in electromagnetic compatibility works. A computational procedure is developped for a quick prevision of the electromagnetic field inten­ sity in the proximal region of a finite overhead line in the frequency range dc-30 MHz. The classical theory of dipole radiation in the presence of a conducting earth is combined with an accurate digital integration technique to provide a solution that is both accurate and straight forward. The response and current distribution of a terminated one-wire transmission line set.over the ground and excited by a non-uniform electromagnetic field is given. The earth conduction effects are con­ sidered. The purpose of such studies is to determine the electromagnetic interferences on data transmission lines arising from the electric resonance of the con­ necting bar in a high-voltage transformer station. A comparison between computer results and experimental measurements is provided.

Body of Revolution Modelling and Applications to EMC

Abstract: Many problems in EMC involve structures which are, either exactly or approximately, rotationally sym­ metric. This property can be used to advantage in a method of moments formulation of a problem, In this paper current and potential capabilities of available body of revolution (BOR) computer codes are described and examples are given. Applications of these codes include radiation and scattering from BORs, coupling through apertures in BORs, and mutual coupling between antennas near a BOR. Also these codes are useful for analyzing bodies that only partially satisfy rotational symmetry. An example is a wire arbitrarily located in the vicinity of a BOR. Another example is coupling through arbitrarily shaped apertures in a BOR.

Needed: A Systems Approach to Electromagnetic Compatibility

Abstract: A proliferation of devices which emit incidental radiation capable of degrading the performance of radio receivers is leading toward a new dimension of federal regulation in the United States. Unacceptable degradation can usually be prevented either by controlling the incidental radiation or by receiver circuitry that minimizes its effects. To protect the consumer--who ultimately pays the bill for regulation--interference caused by incidental radiation devices must be considered on a systems basis and control applied in a method that provides maximum benefit for the costs incurred. /GMRL/

Magnetic and EMC Control of a Deep-Space Satellite Transponder

Abstract: This paper deals with the EMC and Magnetic design and control work carried out on the Transponder section of the spacecraft used in German/US Space Exploration project HELIOS. This project represents a cooperative programme of space research between the United States National Aeronautics and Space Administration and The Ministry for Scientific Research of the German Federal Republic.

Currents Induced on Conducting Rods by Near and Far Zone Sources

Abstract: Missies in flight are often immersed in an elec­ tromagnetic environment. Whether desirable or not, this EMC situation may cause undue influences on per­ formance of on-board subsystems. To measure these effects, it invariably becomes necessary to experimen­ tally test real-life systems on an antenna range. To cover all threats, large frequency bands as well as high field intensities are needed. Thus the use of near-zone transmitting antennas are often required. The simulation validity of such a test arrangement is a cause for concern, since in flight, the missile experiences plane wave incidence. Are there then significant differences in system response when caused by the near-zone source fields compared to plane wave fields? More importantly, how far away does the source have to be to achieve valid simulation? Since the cost of the test facility depends directly on the power needed, which in turn depend on the separation distance, the answers to these questions are therefore of cri­ tical concern.