Showing papers on "Electromagnetic compatibility published in 1984"

Substation Electromagnetic Interference Part 1: Characterization and Description of the Transient EMI Problem

Abstract: The problem of electromagnetic interference with automation and control equipiment in power substations is defined in detail. Instrumentation techniques for measuring electric and Tmagnetic fields are reviewed and actual field data is presented. Several approaches to equipment protection and susceptibility testing are presented from the utility perspective. Examples of transient EHI and conducted interference are included and recommendations are miade as to equipment hardening and design techniques.

A Nonlinear Analysis of the Effects of Transient Electromagnetic Fields on Excitable Membranes

Abstract: The transmembrane voltage produced by a transient electromagnetic field has been determined using a nonlinear model of the cellular membrane The influence on the membrane voltage of the various parameters characterizing the incident field, such as wave-shape, time-width, and amplitude, has been analyzed In particular, the amplitude of the incident field for which the cell's behavior can be assumed as linear and the threshold level for exciting action potentials on the membrane have been determined Potential hazards for humans exposed to transient fields are examined in light of this interaction mechanism

Passive integrating electromagnetic field dosimeter

Abstract: A passive, integrating electromagnetic radiation power dosimeter. A radiofrequency or microwave antenna is combined with a diode detector/rectifier, a squaring circuit, and a electrochemical storage cell to provide an apparatus for determining the average energy of electromagnetic radiation incident on a surface. After a particular period of irradiation, the dosimeter can be interrogated electrically or visually, depending on the type of electrochemical cell employed, to yield the desired information. The apparatus has a substantially linear response to the electromagnetic power density over a wide range of electromagnetic field, and all of the energy required to record the incident energy is supplied by the electromagnetic field.

Conducting Radio Astronomy in the EMC Environment

Abstract: Radio signals from pulsars and distant galaxies are difficult enough to detect on their own, but the problems encountered in making accurate astronomical observations at microwave frequencies are greatly compounded by terrestrial sources of electromagnetic interference (EMI). This paper discusses a wide variety of EMI sources as they affect the operation of radio-astronomy telescopes. These sources can be as simple as a pulsing automotive spark plug or as complex as an aircraft-to-aircraft radio transmission. Various protective countermeasures can be taken; however, compatibility between sensitive microwave receivers and the rest of the radio-frequency (RF) world has yet to be achieved.

Substation Electromagnetic Interference, Part II: Susceptibility Testing and EMI Simulation in High Voltage Laboratories

Abstract: Susceptibility testing techniques for conducted and radiated interference are presented in detail. Withstand levels and test procedures are described. The relationship between substation transients and those generated in high voltage laboratories is discussed with data presented. The problem of instrumentation in these laboratories is presented with quantitative comparisons to substation EilI levels. A qualitative evaluation of those transients which Cdn be generated in thie typical laboratory is included. The use of interference sinmulators is also discussed.

Integrated Circuit Construction and its Effects on EMC Performance

Abstract: The EMC performance o f an electronic product is often evaluated using only one set o f individual components, i.e ., from specific manufacturers w hose components were available at the time o f manufacture. Substitution o f some components o f the same generic type but from other manufacturers can effect the EM C profile o f electronic products. The effect o f integrated circuit construction on EMC performance is discussed. A s an example, a comparison is made o f the performance for six samples o f the same generic integrated cir­ cuit o f the industry standard RS-232C line driver, MC-1488. EMC profiles, X-rays and photomicrographs o f the integrated circuits are included. IN TR O D U C T IO N The many integrated circuits that are incorporated into electro­ nic equipment contribute to the equipment’s electromagnetic emission profile. The maximum emission profile may be specified by any one of the several government regulations or standards such as M IL-STD461B, part 15 o f the Federal Communications Commission Rules and Regulations, etc. The considerable time and effort expended by a manufacturer in meeting these regulations and standards for a specific item o f equipment can be nullified if changes are made to the unit. Changes affecting circuit and mechanical design often are evaluated for their impact on the equipment’s emission profile; however, the substitution o f one vendor’s generic integrated circuit type for another’s is seldom considered. During the manufacturing process, it is com m on to use alternate vendor’s integrated circuits due to cost and availability. Qualification o f alternate vendor parts is normally restricted to form, fit, functional and basic electrical parameters. The emission parameters are seldom considered. This paper discusses the differences in the emission profiles pro­ duced by the industry standard RS-232 line driver from six different vendors.

Statistical Analysis of Digital Circuits Subjected to EMI Induced Delays

Abstract: Specifically, it is shown how to evaluate the pro­ bability the output will be HIGH. This can be used as a measure of system performance. For example, at a specific instant of time assume the output to a known input will be HIGH provided the system is behaving properly. When the system is interfered with, if the probability the output is HIGH at that instant equals 0.8, then the system will be in error in approximately 20% of the cases. By equating the binary output to the value 1 when it is HIGH and to the value 0 when it is LOW, the probability of the output being HIGH equals the statistical average (or expected value) of the out­ put. Hence, performance analysis is reduced to the pro­ blem of evaluating statistical averages.

Demonstration of a Time-Domain Integrated Electromagnetic-Field Circuit-Analysis Program

Abstract: A numerical approach for combining an explicit time-domain electromagnetic computer code with an implicit time-domain circuit code is described. The numerical approach is then demonstrated by predicting plane-wave excitation of a loaded thin wire and the mutual coupling of two thin wires in a box separated by a conductive surface with an aperture. Possible applications to EMC problems are discussed.

The Reference Ground Plane - A Necessity or a Delusion?

Abstract: This paper seeks a fundamental reexamination of the meaning of "reference ground planes", as applicable to E.M.C. measurements. It is suggested that the concept of 'ground planes', while meaningful at low frequencies, may have questionable utility at higher frequencies at which the ground plane dimensions are comparable to or much greater than the wavelength. In the light of these considerations the meaningfulness of standards measurement. procedures and of site characterization techniques is questioned.

Circuit arrangement for improving electromagnetic compatibility in audio-frequency amplifiers

Abstract: In this arrangement, a chip-type capacitor without connecting wires is connected very closely to the electrodes of the input transistor or at the corresponding terminals of the case of an integrated circuit. The chip capacitor is suitably electrically conductively connected directly to two terminals of a so-called spider, provided for connecting the conductors to the semiconductor chip, inside the case of an integrated circuit.

Absorber Lined Chambers for EMC Measurements - A Review

Abstract: This is a review of the evolution, methods of measurement and computational design of Absorber Lined Chambers for e.m. emission and susceptibility measurement purposes. A comprehensive overview of design procedures is presented with illustrative examples of practical ALC's; future development and application trends are discussed.

Electromagnetic Compatibility (EMC) of Power Converters as a Problem of Parametric Optimization

Abstract: In this paper a problem of parametric opti­ mization of power semiconductor converters is considered. It is shown that an account of EMC parameters takes to a significant increase in dimension of elements mathematical models of converter and to generogeneity of their para­ meters variations and to multiextremums of cost functions. Algorithm of quasilinear app­ roximation of a cost function is proposed, allowing to use a finite-difference analogue of gradient methods, having high quickoperation. The check of global character of cost function extremum is made by random search me­ thods .

EMC (Electromagnetic compatibility) spec criteria in Volterra systems

Abstract: : Identification of nonlinear transfer functions (NLTF) and their use in predicting electromagnetic compatibility (EMC) specification parameters such as intermodulation and harmonic distortion was studied. It was assumed that the nonlinear systems of interest can be modeled as lumped parameter circuits with zero-memory nonlinearities between circuit nodes. In this case, the NLTF poles are determined by the poles of the linear transfer function (LTF) of the circuit. Two different cases were considered. In the first case, a transient response measurement of the LTF output can be used to identify the linear system poles. The poles of the LTF then specify the poles of the NLTFs. In the second case, the received signal contains a strong direct path component which is independent of the nonlinear system which is to be identified. This situation arises in the identification of the rusty bolt (a Metal-Insulator-Metal junction). Under this condition, the rusty bolt linear response cannot be measured directly and it is then necessary to estimate the poles of both the LTF and NLTFs from sinusoidal steady state third-order nonlinear response measurements. (Author)

Photonic sensors for electromagnetic field measurements

Abstract: achieve images less than 1 arc-second in diameter, while the space telescope should achieve an image size of less than 0.1 arc-seconds. At.?= 5000 AU the corresponding gain is about 120 dB1 But these are imaging devices, not quite antennas as weknow them. According to Rachel the feeds and receivers, at least at frequencies up to about 400 GHz, will be very similar to those already used at the lower mm wave frequencies. Initially, at frequencies higher than 400 GHz, operation will probably be in an incoherent, i.e. "photon-counting" mode, she expects. She notes that scalar horns have been used as feeds up to 400 GHz, and simple conical' horns at 500 GHz. John Ruze's note enclosed a copy of a paper by Kenji Akabane, titled ''A Large Millimeter Wave Antenna" (International Journal of Infrared and Millimeter Waves, Vol. 4, No. 5, 1983). This paper briefly describes a 45 meter radio telescope at Nobeyama, Japan, with surface roughness of 200 microns. It also contains an interesting listing of nearly two dozen large ( 4 to 45 meter) millimeter wave reflectors, in which the Cal-Tech instrument mentioned above stands out.

Adaptive Pilters Application for Improving Electromagnetic Compatibility of Radio Electronic Equipment

Abstract: Recently adaptive filtering methods are widely applied in automatic control systems, signal separation systems, in adaptive antenna arrays for main beamforming in the direction of the signal and adaptive sidelobe cancelling, in medical electronic apparatus and in some other fields. The report deals with the principles of adaptive filter's creating and analyses the operation algorithm while minimizing the mean-square error. Main_ characteristics of adaptive filters when applied for interference can llation main beam forming adaptive antenna arrays and other purposes are considered. Test results. of adaptive filters on shipboard are shown.

Test Technique for Quickly Locating Conductive Leaks in Shielded Enclosures

Abstract: Users of shielded enclosures usually find that outfitting a 100 dB enclosure with electronic equip­ ment and associated penetrations often results in degraded isolation integrity. This paper presents an effective method for locating shorted penetrations which have resulted in conducted RF leakage to ground. The method is simple, fast and utilizes readily available test equipment. Once understood, this method will allow a technician to quickly locate shorted penetrations which otherwise may take weeks to locate.

Size Reduction of an Indoor EMC Test Site

Abstract: The 3-meter method, the short for a ground reflection EMC test for measurement of radiated emission at a 3-meter test distance, is said to be not only of practical but wellgrounded in theory. One of the main advantages of this method was that it could be tested in the open air., and an expensive anechoic chamber became useless. Now, not a little case, RFwaves in the air mask the radiated emission from a device under test on an open air test site. It is expected that the 3-meter method test site built in an anechoic chamber would contribute to give reliable data. .Details of solving the problems of the 3-meter method test site in an anechoic chamber by using newly de­ veloped cascade type RF absorbers are discussed.