Electromagnetic Interference Control Research Articles

The European ‘EMC’ Directive

A variety of regulations and legislation have been integral part of electromagnetic interference control in the advanced countries. Now we have the existence of Unified approach of European communities for free trade treaty. Knowledge of EMC (Electromagnetic Compatibility) directive implementation approaches with the European Union becomes very essential for manufacturers. This paper will deal with the essential requirements of subject directive.

Measurement of the deuteron polarization in a large target

The 10-probe NMR system for measuring the polarization in the deuterated butanol target of the Spin Muon Collaboration is presented. It is calibrated by determining the integrated spectrum in thermal equilibrium at 1 K. Thermal stabilization and control of electromagnetic interference were effective in reducing drift and electronic noise, so that high quality thermal equilibrium signals were obtained. The calibration constant was determined with a reproducibility of 2%. Systematic effects of circuit drift and of the magnetic field shift have been studied. The resulting 4.4% uncertainty of the calibration dominates the 5% overall error on the target polarization value which was typically 0.45.

Shielding of electromagnetic interference using polyaniline

Since the discovery in 1977 of the metallic properties of molecularly doped polyacetylene, there has been rapid growth in the field of electronically conducting polymers [1-5]. The interest in this area is mainly due to the numerous technological applications of conducting polymers as active electrode materials in energy storage [6], opto-electronic devices [7], display devices [8, 9 ] and their envisaged application for the control of electromagnetic radiation (EMR) and dissipation of electrostatic charge [10-12]. Polyaniline (PAn) is particularly interesting because of the presence of the chemically flexible N H group in the polymer backbone which not only takes part in the protonation/deprotonation but also contributes to 7r-band formation [13], thus ensuring greater environmental stability. PAn can be obtained either by chemical or electrochemical method and does not involve any special precautions [14-16[. Although it is easily synthesized in bulk, its use is restricted due to its unprocessibility by normal melt or solution techniques. For many applications, such as in the control of electromagnetic interference (EMI), dissipation of electrostatic charge (ESD) requires a thin conducting coating on a flexible surface. Polyaniline, unlike metallic coating, is free from corrosion and is very suitable under a highly corrosive atmosphere where other conducting coatings fail. Due to the reactivity of synthetic fabrics like Nylon, Terylene and glass fabric towards mineral acids, we have used organic acids like benzenesulfonic acid (BSA), para-toluenesulfonic acid (PTSA), 5-sulfosalicylic acid (SSA) and 4-hydroxybenzenesulfonic acid as media for grafting PAn. The detailed study using these acids on the properties of polyaniline has been reported elsewhere [8, 9, 17]. The effect of these acids on charge transport, optical and magnetic properties which are quite different to those of mineral acids (like persistence

Antistatic applications of conducting polyaniline

AbstractA method is described to impart flexibility and mechanical strength to conducting polyaniline by polymerizing aniline on fabrics and on cellulose papers. The study indicates that these conducting fabrics offer 16–18 dB of shielding effectiveness for the control of electromagnetic interference (EMI) up to a frequency of 103 MHz.

Ship Topside Integration and Electromagnetic Interference Control

Electromagnetic Interference (EMI) is rapidly becoming one of the major contributors to mission degradation in the U.S. Fleet today. Topside design and integration efforts have been used to reduce EMI, but this is not the total solution to the problem. A program of total ship and system EMI control must be implemented that will span battle groups and be effective during joint operations before optimum combat system effectiveness can be realized. This paper gives examples of some of the major EMI problems in the fleet today. It discusses both intraship and intership EMI problems, how these problems arose, and how they might have been prevented through the use of techniques such as frequency management, equipment design, better element placement and improved cable shielding. It describes the current topside design process, electromagnetic compatibility (EMC) improvements being made and traces the history of EMC requirements and their application to date. It also describes a developing program for managing ship topside arrangement configuration. The authors project where the challenges lie for future topside and EM engineering designers and describe how the equipment acquisition process must improve in order to meet the challenge of effective EMI control.

WATERFRONT CORRECTIVE ACTION PROGRAM (WCAP)/PILOT SHIPYARD PROJECT: RESOLVING EMI PROBLEMS IN CONJUNCTION WITH THE SHIP OVERHAUL PROCESS

ABSTRACTThis paper begins with a discussion of activities toward institutionalization of the control of electromagnetic interference (EMI) during the ship overhaul through the Pilot Shipyard portion of WCAP. The discussion covers such practices as development of training and awareness material, development of standardized documentation to support shipyard activities, establishment of individual ship files of known problems, provision of technical assistance to other shipyards in the resolution of known EMI problems and investigation and development of new installation techniques and processes to insure an extended life span for EMI control hardware installed on board ship. This is in turn followed by a discussion of improvement in pre‐overhaul planning, improvements in existing specifications and standards, the development of model studies and improvements in ships force maintenance procedures to insure that the improvements in overhaul techniques are adopted as a routine institutionalized method.

The need for an organized approach to EMI (electromagnetic interference) control

EMI control refers to the ever-increasing problem of controlling the adverse effects of electromagnetic interference (EMI) on electronic equipment. Atmospheric noise, due to the phenomena of solar radiation and the ionosphere, is one form of ambient interference, but man-made noise adds to the ambient solar interference and increases the ambient intensity by many orders of magnitude. Descriptions are given of several undesirable effects of man-made interference. The interference problem is discussed, as well as many reasons for concern. An approach to EMI control is suggested, including the outline of a proven EMI control program.

Electromagnetic Compatibility of High Density Wiring Installations by Design or Retrofit

Successful integration of individual subsystems in a weapon system depends significantly on the effects of interconnect wiring. Due to increasing complexities of electronic equipments and electrical wiring, problems arise because of the increase in wiring and smaller areas in which it must be placed. To solve a high density wiring problem, McDonnell Aircraft Corp. developed a "compact wire harness" which, when compared to conventional aircraft and spacecraft wiring, reduced harness diameter, improved reliability and appearance, offered more flexibility, and reduced weight appreciably. From the compact wire harness development evolved an additional design "tool" for the control of Electromagnetic Interference (EMI), a "shielded compact wire harness." Continuing product improvements, such as an EMI "tight" backshell, and improved methods to accomplish consistent grounding of the connector plug show favorable promise of adaptibility to the shielded compact wire harness. A recent crippling interference situation in an active Air Force reconnaissance squadron was corrected with the McDonnell shielded cable concept. The usefulness of the process was thereby established as a retrofit "tool."