Pub Date : 1989-05-23DOI: 10.1109/NSEMC.1989.37186
R. H. Haines
A method is presented for quantifying and graphically portraying the extent of use of a frequency band by existing radiocommunication systems. The spectrum use factor quantifies the resources used in a frequency band at a specific location and is defined as the fraction of the total spectrum resources in a frequency band used by existing radiocommunication systems. A computer model calculates the spectrum use factor (SUF) at evenly spaced points in the vicinity of existing transmitters and receivers. The model aggregates the effects of all transmitters and receivers within a geographic area (such as a city, a state. or the continental United States) and creates data files of SUF values from which shaded maps, bar graphs, and indices can be derived.<>
{"title":"An innovative method for quantifying spectrum use","authors":"R. H. Haines","doi":"10.1109/NSEMC.1989.37186","DOIUrl":"https://doi.org/10.1109/NSEMC.1989.37186","url":null,"abstract":"A method is presented for quantifying and graphically portraying the extent of use of a frequency band by existing radiocommunication systems. The spectrum use factor quantifies the resources used in a frequency band at a specific location and is defined as the fraction of the total spectrum resources in a frequency band used by existing radiocommunication systems. A computer model calculates the spectrum use factor (SUF) at evenly spaced points in the vicinity of existing transmitters and receivers. The model aggregates the effects of all transmitters and receivers within a geographic area (such as a city, a state. or the continental United States) and creates data files of SUF values from which shaded maps, bar graphs, and indices can be derived.<<ETX>>","PeriodicalId":408694,"journal":{"name":"National Symposium on Electromagnetic Compatibility","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114391828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1989-05-23DOI: 10.1109/NSEMC.1989.37159
J. Beilfuss, R. Gray
Theoretical development of the multiport injection simulation technique proved that simulation would be exact if the proper multisource excitation was applied at the terminals of the cable. Experiments were performed to demonstrate the accuracy of the approximate Thevenin equivalent source injection technique. Judgement of the accuracy of the approximate technique was based on overlays of the injection cable response with radiating electromagnetic pulse (EMP) simulator data. In order to have a more concise method of determining the quality of an injection simulation, the concept of waveform norm attributes was investigated as a method of estimating the accuracy of a simulation. An IBM PC based software package was developed to compute the norm attributes of digitized data. Results of using the norm attributes as criteria for judging injection simulation quality are discussed.<>
{"title":"Source selection techniques for EMP direct drive simulation","authors":"J. Beilfuss, R. Gray","doi":"10.1109/NSEMC.1989.37159","DOIUrl":"https://doi.org/10.1109/NSEMC.1989.37159","url":null,"abstract":"Theoretical development of the multiport injection simulation technique proved that simulation would be exact if the proper multisource excitation was applied at the terminals of the cable. Experiments were performed to demonstrate the accuracy of the approximate Thevenin equivalent source injection technique. Judgement of the accuracy of the approximate technique was based on overlays of the injection cable response with radiating electromagnetic pulse (EMP) simulator data. In order to have a more concise method of determining the quality of an injection simulation, the concept of waveform norm attributes was investigated as a method of estimating the accuracy of a simulation. An IBM PC based software package was developed to compute the norm attributes of digitized data. Results of using the norm attributes as criteria for judging injection simulation quality are discussed.<<ETX>>","PeriodicalId":408694,"journal":{"name":"National Symposium on Electromagnetic Compatibility","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126467335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1989-05-23DOI: 10.1109/NSEMC.1989.37181
J. D. Gavenda
After a brief discussion of the origin of common-mode currents in interconnect cables, the author discusses the theoretical basis for the effectiveness of common-mode chokes for reducing the common-mode current while leaving the desired differential-mode current undiminished. A method for measuring their actual effectiveness is presented along with measured values for a typical commercial unit. For effective suppression of common-mode currents, the return conductor for a given signal should always be connected to a coil which is closely coupled to the coil carrying the output signal current. For this reason, it is doubtful that effective common-mode current reduction can be achieved in a cable carrying a very large number of signals on parallel conductors unless the signal return paths are relatively well-isolated from one another. This means that great care should be used in laying out the input circuitry of peripheral devices to keep the return currents decoupled.<>
{"title":"Measured effectiveness of a toroid choke in reducing common-mode current","authors":"J. D. Gavenda","doi":"10.1109/NSEMC.1989.37181","DOIUrl":"https://doi.org/10.1109/NSEMC.1989.37181","url":null,"abstract":"After a brief discussion of the origin of common-mode currents in interconnect cables, the author discusses the theoretical basis for the effectiveness of common-mode chokes for reducing the common-mode current while leaving the desired differential-mode current undiminished. A method for measuring their actual effectiveness is presented along with measured values for a typical commercial unit. For effective suppression of common-mode currents, the return conductor for a given signal should always be connected to a coil which is closely coupled to the coil carrying the output signal current. For this reason, it is doubtful that effective common-mode current reduction can be achieved in a cable carrying a very large number of signals on parallel conductors unless the signal return paths are relatively well-isolated from one another. This means that great care should be used in laying out the input circuitry of peripheral devices to keep the return currents decoupled.<<ETX>>","PeriodicalId":408694,"journal":{"name":"National Symposium on Electromagnetic Compatibility","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134329552","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1989-05-23DOI: 10.1109/NSEMC.1989.37147
Y.M. Lee, J. Latess
Results are presented from tests of a prototype wire-mesh electromagnetic interference (EMI) gasket with an inflatable core. The gasket is constructed of several layers of wire mesh woven around an air-inflatable rubber core. The wire mesh is made of tin-coated copper-clad steel. It is noted that all testing was performed in an environmentally controlled area. The purpose was to examine the core material for compression set and not to test the wire-mesh material for galvanic corrosive performance. The inflatable rubber-core wire-mesh gasket showed shielding values approaching 70 dB at 150-kHz frequency, and it is expected that this could be improved with a larger core. The cost of the prototype gasket was relatively expensive; however, this cost was influenced largely by the number of layers of wire mesh (five on the prototype). It is believed that this number can be reduced to at most two by use of a larger rubber core. The high-pressure air bottles, regulator, and gauges could also be replaced with a simple, less expensive setup once a final gasket configuration is decided upon.<>
{"title":"Performance of wire mesh gaskets with air-inflatable core","authors":"Y.M. Lee, J. Latess","doi":"10.1109/NSEMC.1989.37147","DOIUrl":"https://doi.org/10.1109/NSEMC.1989.37147","url":null,"abstract":"Results are presented from tests of a prototype wire-mesh electromagnetic interference (EMI) gasket with an inflatable core. The gasket is constructed of several layers of wire mesh woven around an air-inflatable rubber core. The wire mesh is made of tin-coated copper-clad steel. It is noted that all testing was performed in an environmentally controlled area. The purpose was to examine the core material for compression set and not to test the wire-mesh material for galvanic corrosive performance. The inflatable rubber-core wire-mesh gasket showed shielding values approaching 70 dB at 150-kHz frequency, and it is expected that this could be improved with a larger core. The cost of the prototype gasket was relatively expensive; however, this cost was influenced largely by the number of layers of wire mesh (five on the prototype). It is believed that this number can be reduced to at most two by use of a larger rubber core. The high-pressure air bottles, regulator, and gauges could also be replaced with a simple, less expensive setup once a final gasket configuration is decided upon.<<ETX>>","PeriodicalId":408694,"journal":{"name":"National Symposium on Electromagnetic Compatibility","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125003092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1989-05-23DOI: 10.1109/NSEMC.1989.37212
L. Hoeft, T. Salas, J. Hofstra, W. Prather
Polarizability theory was applied to the problem of predicting the shielding effectiveness of a conductive shield with a well-defined aperture. Shielding effectiveness was defined by both MIL-STD-285 (ratio of the fields at a prescribed point with and without the shield in place) and the ratio of the magnetic field outside and inside of a shield. Relatively simple relationships were derived when the aperture was electrically small and the shield behaved like a plane conducting sheet. These relationships were consistent with measured values, and allow calibration apertures to be used to establish the credibility of shielding effectiveness measurements. It is noted that shielding effectiveness and surface magnetic-field attenuation are both strong functions of the distance between the measurement location and the shield. Thus, both are not intrinsic electromagnetic parameters.<>
{"title":"Predicted shielding effectiveness of apertures in large enclosures as measured by MIL-STD-285 and other methods","authors":"L. Hoeft, T. Salas, J. Hofstra, W. Prather","doi":"10.1109/NSEMC.1989.37212","DOIUrl":"https://doi.org/10.1109/NSEMC.1989.37212","url":null,"abstract":"Polarizability theory was applied to the problem of predicting the shielding effectiveness of a conductive shield with a well-defined aperture. Shielding effectiveness was defined by both MIL-STD-285 (ratio of the fields at a prescribed point with and without the shield in place) and the ratio of the magnetic field outside and inside of a shield. Relatively simple relationships were derived when the aperture was electrically small and the shield behaved like a plane conducting sheet. These relationships were consistent with measured values, and allow calibration apertures to be used to establish the credibility of shielding effectiveness measurements. It is noted that shielding effectiveness and surface magnetic-field attenuation are both strong functions of the distance between the measurement location and the shield. Thus, both are not intrinsic electromagnetic parameters.<<ETX>>","PeriodicalId":408694,"journal":{"name":"National Symposium on Electromagnetic Compatibility","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116858047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1989-05-23DOI: 10.1109/NSEMC.1989.37210
H. Suzuki, H. Furuta, K. Davis
Electromagnetic leakage from coaxial cables, (i.e. shielding effectiveness of coaxial cables) was successfully measured as an absolute value over a frequency range from 4 GHz to 18 GHz using a simple, compact test system composed of parabolic cylinder reflector antennas. In combination with a regular vector network analyzer and high-frequency power amplifier, this system allows shield-effectiveness measurements without the need for a shielded room. The dynamic range of this system is approximately 85 dB, allowing shield-effectiveness measurements for various types of coaxial cable shieldings with good reproducibility. The test results are similar to those obtained by standard methods, indicating the possibility of shielding effectiveness measurements even for higher-frequency ranges such as the millimeter-wave range.<>
{"title":"Wideband RF-leakage test method for cables","authors":"H. Suzuki, H. Furuta, K. Davis","doi":"10.1109/NSEMC.1989.37210","DOIUrl":"https://doi.org/10.1109/NSEMC.1989.37210","url":null,"abstract":"Electromagnetic leakage from coaxial cables, (i.e. shielding effectiveness of coaxial cables) was successfully measured as an absolute value over a frequency range from 4 GHz to 18 GHz using a simple, compact test system composed of parabolic cylinder reflector antennas. In combination with a regular vector network analyzer and high-frequency power amplifier, this system allows shield-effectiveness measurements without the need for a shielded room. The dynamic range of this system is approximately 85 dB, allowing shield-effectiveness measurements for various types of coaxial cable shieldings with good reproducibility. The test results are similar to those obtained by standard methods, indicating the possibility of shielding effectiveness measurements even for higher-frequency ranges such as the millimeter-wave range.<<ETX>>","PeriodicalId":408694,"journal":{"name":"National Symposium on Electromagnetic Compatibility","volume":"109 2-3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126998541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1989-05-23DOI: 10.1109/NSEMC.1989.37184
M. Nave
A differential mode rejection network (DMRN), a device which separates common mode noise from differential mode noise in a line impedance stabilization network (LISN)-based conducted emissions setup, is described. Although it is not a filter, its function is analogous to that of a filter. The DMRN filters out differential mode, and passes common mode unfiltered. The differential mode is attenuated by more than 50 dB, and the common mode noise is attenuated by less than 4 dB. Applications of the DMRN are discussed for filter design and troubleshooting, and electromagnetic interference source suppression is briefly described. Mathematical analysis and hardware implementation of the devices are explained.<>
{"title":"A novel differential mode rejection network for conducted emissions diagnostics","authors":"M. Nave","doi":"10.1109/NSEMC.1989.37184","DOIUrl":"https://doi.org/10.1109/NSEMC.1989.37184","url":null,"abstract":"A differential mode rejection network (DMRN), a device which separates common mode noise from differential mode noise in a line impedance stabilization network (LISN)-based conducted emissions setup, is described. Although it is not a filter, its function is analogous to that of a filter. The DMRN filters out differential mode, and passes common mode unfiltered. The differential mode is attenuated by more than 50 dB, and the common mode noise is attenuated by less than 4 dB. Applications of the DMRN are discussed for filter design and troubleshooting, and electromagnetic interference source suppression is briefly described. Mathematical analysis and hardware implementation of the devices are explained.<<ETX>>","PeriodicalId":408694,"journal":{"name":"National Symposium on Electromagnetic Compatibility","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127430521","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1989-05-23DOI: 10.1109/NSEMC.1989.37154
I. Straus
The planned European Community (EC) directive on electromagnetic compatibility has as its goal the establishment of uniform technical standards and marketing procedures. While international emissions standards are well established, immunity specifications are far less agreed upon. The author discusses the shape that immunity requirements for information technology equipment may take. He reviews the main topics the directive is expected to cover. These are the performance limits, test methods and their relation to existing standards for continuous magnetic fields, electromagnetic field immunity, conducted susceptibility, power system transient immunity, and electrostatic discharge immunity.<>
{"title":"European immunity requirements: a preview","authors":"I. Straus","doi":"10.1109/NSEMC.1989.37154","DOIUrl":"https://doi.org/10.1109/NSEMC.1989.37154","url":null,"abstract":"The planned European Community (EC) directive on electromagnetic compatibility has as its goal the establishment of uniform technical standards and marketing procedures. While international emissions standards are well established, immunity specifications are far less agreed upon. The author discusses the shape that immunity requirements for information technology equipment may take. He reviews the main topics the directive is expected to cover. These are the performance limits, test methods and their relation to existing standards for continuous magnetic fields, electromagnetic field immunity, conducted susceptibility, power system transient immunity, and electrostatic discharge immunity.<<ETX>>","PeriodicalId":408694,"journal":{"name":"National Symposium on Electromagnetic Compatibility","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129820545","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1989-05-23DOI: 10.1109/NSEMC.1989.37155
D. Dixon
The author suggests that time and money could be saved and more meaningful electromagnetic interference (EMI) test results could be obtained if existing MIL-STD EMI test procedures were modified to permit cabinet (unit) level testing to be conducted while having the total system electronics interconnected in a system-level environment. He proposes a concept in which electronic systems consisting of more than one cabinet could be EMI tested while configured and operating in a system-level, testbed type of environment. This would require the development of a portable electromagnetically isolated test chamber that has built-in near-field measurement sensors that permit the chamber to be utilized in an oversized system development laboratory which has been peripherally shielded with copper screening.<>
{"title":"Radiated emission and susceptibility EMI testing: the advantages of conducting unit level tests in a system level environment","authors":"D. Dixon","doi":"10.1109/NSEMC.1989.37155","DOIUrl":"https://doi.org/10.1109/NSEMC.1989.37155","url":null,"abstract":"The author suggests that time and money could be saved and more meaningful electromagnetic interference (EMI) test results could be obtained if existing MIL-STD EMI test procedures were modified to permit cabinet (unit) level testing to be conducted while having the total system electronics interconnected in a system-level environment. He proposes a concept in which electronic systems consisting of more than one cabinet could be EMI tested while configured and operating in a system-level, testbed type of environment. This would require the development of a portable electromagnetically isolated test chamber that has built-in near-field measurement sensors that permit the chamber to be utilized in an oversized system development laboratory which has been peripherally shielded with copper screening.<<ETX>>","PeriodicalId":408694,"journal":{"name":"National Symposium on Electromagnetic Compatibility","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132839139","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1989-05-23DOI: 10.1109/NSEMC.1989.37199
S.B. Safford, M. Obara
Electromagnetic interference testing of video equipment reveals that both monochrome and color cathode-ray tube (CRT) monitors are susceptible to picture distortions due to DC magnetic fields. The most common commercially available color CRTs use shadow mask technology. These CRTs, however, are the most susceptible to DC magnetic fields due to their precise alignment requirements for color convergence and registration. Testing on the CRT display systems was conducted to determine equipment compatibility to the magnetic field environment as defined in DOD-STD-1399, Section 070. Measurements were taken to determine the levels at which degradations begin to appear. Mu-metal and carbon steel shields were constructed and evaluated for their shielding effectiveness. Shadow mask color CRTs are more susceptible to DC magnetic fields than monochrome CRTs. The color CRTs have all the problems associated with the monochrome CRTs, with the additional problems due to their precise alignment requirements necessary for color convergence and registration. Preliminary results show that simple metallic shielding using magnetic materials, by itself, is only effective for static, low-level DC magnetic fields. The use of massive, multilayered shields in dynamic environments with fields larger than 400 A/m. is impractical and not cost effective. Deperming circuitry, along with the shielding, can be used to cancel the higher-level external fields.<>
{"title":"DC magnetic field effects on shadow mask color cathode-ray tube (CRT) performance","authors":"S.B. Safford, M. Obara","doi":"10.1109/NSEMC.1989.37199","DOIUrl":"https://doi.org/10.1109/NSEMC.1989.37199","url":null,"abstract":"Electromagnetic interference testing of video equipment reveals that both monochrome and color cathode-ray tube (CRT) monitors are susceptible to picture distortions due to DC magnetic fields. The most common commercially available color CRTs use shadow mask technology. These CRTs, however, are the most susceptible to DC magnetic fields due to their precise alignment requirements for color convergence and registration. Testing on the CRT display systems was conducted to determine equipment compatibility to the magnetic field environment as defined in DOD-STD-1399, Section 070. Measurements were taken to determine the levels at which degradations begin to appear. Mu-metal and carbon steel shields were constructed and evaluated for their shielding effectiveness. Shadow mask color CRTs are more susceptible to DC magnetic fields than monochrome CRTs. The color CRTs have all the problems associated with the monochrome CRTs, with the additional problems due to their precise alignment requirements necessary for color convergence and registration. Preliminary results show that simple metallic shielding using magnetic materials, by itself, is only effective for static, low-level DC magnetic fields. The use of massive, multilayered shields in dynamic environments with fields larger than 400 A/m. is impractical and not cost effective. Deperming circuitry, along with the shielding, can be used to cancel the higher-level external fields.<<ETX>>","PeriodicalId":408694,"journal":{"name":"National Symposium on Electromagnetic Compatibility","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127079809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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