1.Product Manager: Karen FeinsteinProject Editor:Ibrey WoodallPackaging design:Jonathan PennellThese les shall remain the sole and exclusive property of CRC Press LLC, 2000 Corporate Blvd., N.W., Boca Raton, FL 33431.The contents are protected by copyright law and international treaty. No part of the Electrical Engineering Dictionary CRCnetBASECD-ROM product may be duplicated in hard copy or machine-readable form without prior written authorization from CRC PressLLC, except that the licensee is granted a limited, non-exclusive license to reproduce limited portions of the context for the licenseesinternal use provided that a suitable notice of copyright is included on all copies. This CD-ROM incorporates materials from othersources reproduced with the kind permission of the copyright holder. Credit to the original sources and copyright notices are givenwith the gure or table. No materials in this CD-ROM credited to these copyright holders may be reproduced without their writtenpermission.WARRANTY The information in this product was obtained from authentic and highly regarded sources. Every reasonable effort has beenmade to give reliable data and information, but the publisher cannot assume responsibility for the validity of all materials or theconsequences of their uses. 2000 by CRC Press LLCNo claim to original U.S. Government worksInternational Standard Book Number 0-8493-2170-0International Standard Series Number 1097-9568 2000 by CRC Press LLC

2. Preface One can only appreciate the magnitude of eort required to develop a dictionary by actually experiencing it. Although I had written nine other books, I certainly did not know what I was getting into when in January of 1996 I agreed to serve as Editor-in- Chief for this project. Now, after 2 1/2 years I understand.Unlike other books that I have written, creating this dictionary was more a test of will and stamina and an exercise in project management than mere writing. And although I have managed organizations of up to 80 academics, nothing is more like herding cats than motivating an international collection of almost 200 distinguished engineers, scientists, and educators scattered around the globe almost entirely via email. Yet, I think there is no other way to undertake a project like this. I still marvel at how Noah Webster must have managed to construct his English Dictionary without the benets of modern communication.But this project, as much as it is a monument to individual will, is really the collaborative work of many brilliant and dedicated men and women. This is their dictionary and your dictionary.Phillip A. Laplante, PE, Ph.D.Editor-in-ChiefPresident Pennsylvania Institute of Technology Media, Pennsylvania 2000 CRC Press LLC 3. Editorial Board E.R. Davies Andrew Kahng University of LondonUniversity of California at Berkeley Associate Editor: Signal andCo-Editor: Digital electronics, VLSI, Image Processing hardware description language Mike FiddyMark Kinsler University of Massachusetts, Lowell Editor: Power systems Editor: Electro-optical and lightwave systems Mike GolioLauren Laplante Rockwell CollinsPublic Service Electric and Gas Editor: Microwave systems Editor: Properties of materials Marco GoriSudhakar Muddu University of FlorenceSilicon Graphics Associate Editor: Information ProcessingCo-Editor: Digital electronics, VLSI,hardware description language Ling Guan Meredith Nole University of SydneyAmerican Efcient Lighting Editor: Communications and informationEditor: Illumination processing Bob Herrick Amos Omondi Purdue University Flinders University Editor: RF, radio and televisionEditor: Computer engineering (I/O and storage) Jeff Honchell Ian Oppermann Purdue University University of Sydney Associate Editor: RF, radio and televisionAssociate Editor: Communication Jin Jiang John Prince University of Western Ontario University of Arizona Editor: Circuits and systemsEditor: Packaging Tadeusz KaczorekMark Reed Warsaw University of Technology Yale University Editor: Control systems Editor: Microelectronics and solid state devices 2000 CRC Press LLC 4. David Shively Eugene VeklerovShively Engineering Lawrence Berkeley LabsEditor: ElectromagneticsEditor: Signal and image processingTim SkvareninaJanusz ZalewskiPurdue University University of Central FloridaEditor: Electric machines and power electronics Editor: Computer engineering (processors) 2000 CRC Press LLC 5. ForewordHow was the dictionary constructed?As I knew this project would require a divide-and-conquer approach with fault-tolerance, I sought to partition the dictionary by dening areas that covered all aspectsof Electrical Engineering. I then matched these up to IEEE dened interest areas toensure that complete coverage was provided. This created a great deal of overlap,which was intentional. I knew that terms needed to be dened several dierent ways,depending on usage and I needed to ensure that every term would be dened at leastonce. The mapping of the Dictionarys areas to the IEEE interest areas are as follows: Power systems Circuits and systems Power Engineering Circuits and Systems Power Electronics Instruments and Measurements Electric motors and machinesControl systems Power Engineering Control Systems Power Electronics Robotics and Automation Digital electronics, VLSI, hardware Electromagneticsdescription language Electromagnetic Compatibility Consumer Electronics Magnetics Electronic Devices Industrial Electronics Instruments and Measurements Computer engineering (processors) Computer Microelectronics and solid state devices Industrial ElectronicsComputer engineering (I/O and storage) Instruments and Measurements Computer RF, radio, and television Microwave systems Broadcast Technology Antennas and Propagation Microwave Theory and Techniques Communications and information processing CommunicationsElectro-optical and lightwave systems Information Theory Lasers and Electro-Optics Systems, Man, and Cybernetics Reliability Illumination Signal and image processing Properties of materials Signal Processing Dielectrics and Electrical Insulation Systems, Man, and Cybernetics Packaging Components, Packaging, and Manufacturing TechnologyNote that Software Engineering was not included as an area, and most softwareterms have been omitted. Those that were included were done so because they relateto some aspect of assembly language programming or low-level control, or articialintelligence and robotics. For those interested in software engineering terms, CRCs 2000 CRC Press LLC 6. forthcoming Comprehensive Dictionary of Computer Science, Engineering and Tech-nology will include those terms.Several other IEEE interest areas were not explicitly assigned to area editors. How-ever, after discussing this fact with the Editorial Board, it was decided that relevantterms of a general nature would be picked up and terms that were not tagged for thedictionary from these areas were probably too esoteric to be included.These interest areas encompass:Aerospace and Electronic SystemsGeosience and Remote SensingEducation Industry ApplicationsEngineering in Medicine and Biology Nuclear and Plasma ScienceEngineering ManagementOceanic EngineeringProfessional Communications Ultrasonic, Ferroelectrics, and Frequency ControlSocial Implications of Technology Vehicular Technology Given the Area Editor structure, constructing the dictionary then consisted of thefollowing steps: 1. Creating a terms list for each area 2. Dening terms 3. Cross-checking terms within areas 4. Cross-checking terms across areas 5. Compiling and proong the terms and denitions 6. Reviewing compiled dictionary 7. Final proofreading The rst and most important task undertaken by the area editors was to develop alist of terms to be dened. A terms list is a list of terms (without denitions), propernames (such as important historical gures or companies), or acronyms relating toElectrical Engineering. What went into each terms list was left to the discretion of thearea editor based on the recommendations of the contributing authors. However, listswere to include all technical terms that relate to the area (and subareas). Technicalterms of a historical nature were only included if it was noted in the denition thatthe term is not used in modern engineering or that the term is historical only.Although the number of terms in each list varied somewhat, each areas terms listconsisted of approximately 700 items. Once the terms lists were created, they were merged and scrutinized for any obviousomissions. These missing terms were then assigned to the appropriate area editor.At this point the area editors and their contributing authors (there were 5 to 20contributing authors per area) began the painstaking task of term denition. Thisprocess took many months. Once all of the terms and their denitions were collected,the process of converting, merging, and editing began. The dictionary included contributions from almost 200 contributors from 17 coun-tries. Although authors were provided with a set of guidelines to write terms def-initions, they were free to exercise their own judgment and to use their own style. 2000 CRC Press LLC 7. As a result, the entries vary widely in content from short, one-sentence denitions torather long dissertations. While I tried to provide some homogeneity in the process ofediting, I neither wanted to tread on the feet of the experts and possibly corrupt themeaning of the denitions (after all, I am not an expert in any of the representativeareas of the dictionary) nor did I want to interfere with the individual styles of theauthors. As a result, I think the dictionary contains a diverse and rich expositionthat collectively provides good insights into the areas intended to be covered by thedictionary. Moreover, I was pleased to nd the resultant collection much more lively,personal, and user-friendly than typical dictionaries. Finally, we took advantage of the rich CRC library of handbooks, including TheControl Handbook, Electronics Handbook, Image Processing Handbook, Circuits andFilters Handbook, and The Electrical Engineering Handbook, to pick up any deni-tions that were missing or incomplete. About 1000 terms were take from the CRChandbooks. We also borrowed, with permission from IEEE, about 40 denitions thatcould not be found elsewhere or could not be improved upon. Despite the incredible support from my area editors, individual contributors, andsta at CRC Press, the nal task of arbitrating conicting denitions, rewording thosethat did not seem descriptive enough, and identifying missing ones was left to me. Ihope that I have not failed you terribly in my task.How to use the dictionaryThe dictionary is organized like a standard language dictionary except that not ev-ery word used in the dictionary is dened there (this would necessitate a completeembedding of an English dictionary). However, we tried to dene most non-obvioustechnical terms used in the denition of another term. In some cases more than one denition is given for a term. These are denoted (1),(2), (3), . . ., etc. Multiple denitions were given in cases where the term has multipledistinct meanings in diering elds, or when more than one equivalent but uniquelydescriptive denition was available to help increase understanding. In a few cases, Ijust couldnt decide between two denitions. Pick the denition that seems to t yoursituation most closely. The notation 1., 2., etc. is used to itemize certain elements ofa denition and are not to be confused with multiple denitions. Acronym terms are listed by their expanded name. Under the acronym the reader isreferred to that term. For example, if you look up RISC you will nd See reducedinstruction set computer, where the denition can be found. The only exceptionsare in the cases where the expanded acronym might not make sense, or where theacronym itself has become a word (such as laser or sonar). While I chose to include some commonly used symbols (largely upon the recom-mendations of the contributors and area editors), this was not a principle focus of thedictionary and I am sure that many have been omitted. 2000 CRC Press LLC 8. Finally, we tried to avoid proprietary names and tradenames where possible. Somehave crept in because of their importance, however.AcknowledgmentsA project of this scope literally requires hundreds of participants. I would like to takethis moment to thank these participants both collectively and individually. I thank,in no particular order: The editorial board members and contributors. Although not all partici- pated at an equal level, all contributed in some way to the production of this work. Ron Powers, CRC President of Book Publishing, for conceiving this dictio- nary, believing in me, and providing incredible support and encouragement. Frank MacCrory, Norma Trueblood, Nora Konopka, Carole Sweatman, and my wife Nancy for converting, typing, and/or entering many of the terms. Jill Welch, Nora Konopka, Ron Powers, Susan Fox, Karen Feinstein, Joe Ganzi, Gerry Axelrod, and others from CRC for editorial support. CRC Comprehensive Dictionary of Mathematics and CRC Comprehensive Dictionary of Physics editor Stan Gibilisco for sharing many ideas with me. My friend Peter Gordon for many of the biographical entries. Lisa Levine for providing excellent copy editing of the nal manuscript. Finally to my wife Nancy and children Christopher and Charlotte for their incrediblepatience and endurance while I literally spent hundreds of hours to enable the birthof this dictionary. This achievement is as much theirs as it is mine. Please accept my apologies if anyone was left out this was not intentional andwill be remedied in future printings of this dictionary.How to Report Errors/OmissionsBecause of the magnitude of this undertaking and because we attempted to developnew denitions completely from scratch, we have surely omitted (though not deliber-ately) many terms. In addition, some denitions are possibly incomplete, weak, or evenincorrect. But we wish to evolve and improve this dictionary in subsequent printingsand editions. You are encouraged to participate in this collaborative, global process.Please send any suggested corrections, improvements, or new terms to be added (alongwith suggested denitions) to me at p.laplante@ieee.org or plaplante@pit.edu.If your submission is incorporated, you will be recognized as a contributor in futureeditions of the dictionary. 2000 CRC Press LLC 9. Editor-in-ChiefPhil Laplante is the President of Pennsylvania Institute of Technology, a two-year,private, college that focuses on technology training and re-training. Prior to this,he was the founding dean of the BCC/NJIT Technology and Engineering Center inSouthern New Jersey. He was also Associate Professor of Computer Science andChair of the Mathematics, Computer Science and Physics Department at FairleighDickinson University, New Jersey. In addition to his academic career, Dr. Laplantespent almost eight years as a software engineer designing avionics systems, a microwaveCAD engineer, a software systems test engineer, and a consultant. He has written dozens of articles for journals, newsletters, magazines, and confer-ences, mostly on real-time computing and image processing. He has authored 10 othertechnical books and edits the journal, Real-Time Imaging, as well as two book seriesincluding the CRC Press series on Image Processing. Dr. Laplante received his B.S., M.Eng., and Ph.D. in Computer Science, ElectricalEngineering, and Computer Science, respectively, from Stevens Institute of Technologyand an M.B.A. from the University of Colorado at Colorado Springs. He is a senior member of IEEE and a member of ACM and numerous other pro-fessional societies, program committees, and advisory boards. He is a licensed profes-sional engineer in New Jersey and Pennsylvania. Dr. Laplante is married with two children and resides in Pennsylvania. 2000 CRC Press LLC 10. References [1] Attasi, Systemes lineaires homgenes a deux indices, IRIA Rapprot Laboria, No. 31, Sept. 1973. [2] Baxter, K., Capacitive Sensors, IEEE Press, 1997. [3] Biey and Premoli, A., Cauer and MCPER Functions for Low-Q Filter Design, St. Saphorin: Georgi, 1980. [4] Blostein, L., Some bounds on the sensitivity in RLC networks, Proceedings of the 1st Allerton Conference on Circuits and Systems Theory, 1963, pp. 488501. 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IEEE, 65(6), 861872, 1977.[34] Myers, J., Advances in Computer Architecture, 2nd ed., New York: John Wiley & Sons, 1982.[35] Neubert, K.P., Instrument Transducers, Clarendon Press, 1975.[36] Qiu, S.-S. and Filanovsky, I.M., Periodic solutions of the Van der Pol equation with mod- erate values of damping coefcient, IEEE Transactions on Circuits and Systems, CAS-34, 913918, 1987.[37] Orchard, J., Loss sensitivities in singly and doubly terminated lters, IEEE Transac- tions on Circuits and Systems, CAS-26, 293297, 1979.[38] Pallas-Ar ny and Webster, J.G., Sensor and Signal Conditioning, New York: John a Wiley & Sons, 1991.[39] Patterson, A. and Ditzel, D.R., The case for the RISC, Computer Architecture News, 8(6), 2533, 1980.[40] Patterson, A. and Sequin, C.H., A VLSI RISC, IEEE Computer, 15(9), 821, 1982.[41] Pederson, O. and Mayaram, K., Analog Integrated Circuits for Communication, Kluwer, 1991. 2000 CRC Press LLC 12. [42] Radin, The 801 Minicomputer, IBM J. Res. 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ContributorsJames T. Aberle Partha P. BanjereeArizona State UniversityUniversity of AlabamaTempe, AZ Huntsville, ALGiovanni Adorni Ishmael (Terry) BanksUniversit di Parma American Electric Power CompanyParma, ItalyAthens, OHAshfaq AhmedWalter BanzhafPurdue University University of HartfordWest Lafayette, INHartford, CTA. E. A. AlmainiOttis L. BarronNapier University University of Tennessee at MartinEdinburgh, Scotland Martin, TNEarle M. Alexander IV Robert A. BartkowiakSan Rafael, CAPenn State University at Lehigh ValleyFogelsville, PAJim AndrewCISRA Richard M. BassNorth Ryde, Australia Georgia Institute of TechnologyAtlanta, GAJames AntonakosBroome County Community College Michael R. BastianBinghampton, NY Brigham Young UniversityProvo, UTEduard AyguadeBarcelona, SpainJeffrey S. BeasleyNew Mexico State UniversityBibhuti B. Banerjee Las Cruces, NMDexter Magnetic MaterialsFremont, CA Lars BengtssonHalmsted UniversityHalmsted, Sweden 2000 by CRC Press LLC 14. Mi BiAntonio ChellaTai Seng Industrial Estate University of PalermoSingaporePalermo, ItalyEdoardo Biagioni C. H. ChenSCSUniversity of MassachusettsPittsburgh, PA N. Dartmouth, MADavid L. Blanchard Zheru ChiPurdue University CalumetHong Kong Polytechnic UniversityHammond, INHung Hom, Kowloon, Hong KongWayne Bonzyk Shamala ChickamenahalliColman, SD Wayne State University Detroit, MIR. W. BoydUniversity of RochesterChristos ChristodoulouRochester, NYUniversity of Central Florida Orlando, FLM. BraaeUniversity of Cape TownBadrul ChowdhuryRondebosch, South Africa University of Wyoming Laramie, WyomingDoug BurgesUniversity of WisconsinDominic J. CiardulloMadison, WINassau Community College Garden City, NYNick BurisMotorola Andrew CobbSchaumburg, IL New Albany, INJose Roberto Camacho Christopher J. ConantUniversidade Federal de Uberlindia Broome County Community CollegeUberlindia, Brazil Binghamton, NYGerard-Andre CapolinoRobin CraveyUniversity of Picardie NASA Langley Research CenterAmiens, France Hampton, VALee W. Casperson George W. CrawfordPortland State UniversityPenn State UniversityPortland, OR McKeesport, PA 2000 by CRC Press LLC 15. John K. Daher Andrzej DzielinskiGeorgia Institute of Technology ISEPAtlanta, GA Warsaw University of TechnologyWarsaw, PolandFredrik DahlgrenChalmers University of Technology Jack EastGothenburg, SwedenUniversity of MichiganAnn Arbor, MIE. R. DaviesUniversity of LondonSandra EitnierSurrey, England San Diego, CARonald F. DeMaraSamir El-GhazalyUniversity of Central Florida Arizona State UniversityOrlando, FL Tempe, AZWilliam E. DeWitt Irv EnglanderPurdue University Bentley CollegeWest Lafayette, INWaltham, MAAlex DomijanIvan FairUniversity of Florida Technical University of Nova ScotiaGainesville, FL Halifax, Nova Scotia, CanadaBob DonyGang FengUniversity of GuelphUniversity of New South WalesGuelph, Ontario, Canada Kensington, AustraliaTom Downs Peter M. FenwickUniversity of QueenslandUniversity of AucklandBrisbane, Australia Auckland, New ZealandMarvin DrakePaul FieguthThe MITRE Corporation University of WaterlooBedford, MA Waterloo, Ontario, CanadaLawrence P. DunleavyIgor FilanovskyUniversity of South Florida University of AlbertaTampa, FL Edmonton, Alberta, CanadaScott C. DunningWladyslau FindeisenUniversity of Maine Warsaw University of TechnologyOrono, ME Warsaw, Poland 2000 by CRC Press LLC 16. Dion Fralick P. R. HemmerNASA Langley Research Center RL/EROPHampton, VAHanscom Air Force Base, MALawrence Fryda Vincent HeuringCentral Michigan UniversityUniversity of ColoradoMt. Pleasant, MI Boulder, COMumtaz B. GawargyAndreas HirsteinConcordia University Swiss Electrotechnical AssociationMontreal, Quebec, Canada Fehraltorf, SwitzerlandFrank GerlitzRobert J. HongerWashtenaw CollegePurdue University School ofAnn Arbor, MITechnology at Columbus Columbus, INAntonio Augusto GorniCOSIPA Michael HonigCubatao, BrazilNorthwestern University Evanston, ILLee GoudelockLaurel, MS Yan Hui Northern TelecomAlex Grant Nepean, Ontario, CanadaInstitut fr Signal- und InformationsverarbeitungSuresh HungenahallyZurich, SwitzerlandGriffth University Nathan, Queensland, AustraliaThomas G. HabetlerGeorgia Tech Iqbal HusainAtlanta, GAUniversity of Akron Akron, OHHaldun HadimiogluPolytechnic University Eoin HydenBrooklyn, NY Madison, NJDave Halchin Marija IlicRF MicroDevicesMITGreensboro, NC Cambridge, MAThomas L. Harman Mark JanosUniversity of HoustonUniphase Fiber ComponentsHouston, TXSydney, Australia 2000 by CRC Press LLC 17. Albert JelalianDavid KelleyJelalian Science & Engineering Penn State UniversityBedford, MAUniversity Park, PAAnthony JohnsonD. KennedyNew Jersey Institute of Technology Ryerson Polytechnic InstituteNewark, NJ Toronto, Ontario, CanadaC. Bruce Johnson Mohan KetkarPhoenix, AZUniversity of Houston Houston, TXBrendan JonesOptus Communications Jerzy KlamkaSydney, AustraliaSilesian Technical University Gliwice, PolandSuganda JutamuliaIn-Harmony Technology Corp.Krzysztof KozlowskiPetaluma, CA Technical University of Poznan Poznan, PolandRichard Y. KainUniversity of MinnesotaRon LandMinneapolis, MNPenn State University New Kensington, PADikshitulu K. KalluriUniversity of MassachusettsRobert D. LaramoreLowell, MA Cedarville College Cedarville, OHAlex KaluSavannah State UniversityJoy LaskarSavannah, GA Georgia Institute of Technology Atlanta, GAGary KamermanFastMetrix Matti Latva-ahoHuntsville, AL University of Oulu Linannmaa, Oulu, FinlandAvishay KatzEPRI Thomas S. LaverghettaPalo Alto, CAIndiana University-Purdue Universityat Fort WayneWilson E. KazibweFort Wayne, INTelegyr SystemsSan Jose, CA J. N. Lee Naval Research Laboratory Washington, D. C. 2000 by CRC Press LLC 18. Fred Leonberger John A. McNeillUT PhotonicsWorcester Polytechnic InstituteBloomeld, CT Worcester, MAGing Li-WangDavid P. MillardDexter Magnetic Materials Georgia Institute of TechnologyFremont, CA Atlanta, GAYilu LiuMonte MillerVirginia Tech Rockwell Semiconductor SystemsBlacksburg, VANewbury Park, CAJean Jacques LoiseauLinn F. MollenauerInstitute Recherche en Cybernetique AT&T Bell LabsNantes, FranceHolmdel, NJHarry MacDonald Mauro MongiardoSan Diego, CA University of PerugiaPerugia, ItalyChris MackFINLE TechnologiesMichael A. MorganAustin, TXNaval Postgraduate SchoolMonterey, CAKrzysztov MalinowskiWarsaw University of Technology Amir MortazawiWarsaw, PolandUniversity of Central FloridaOrlando, FLS. ManoharanUniversity of AucklandMichael S. MunozAuckland, New Zealand TRW CorporationHoracio J. MarquezPaolo NesiUniversity of Alberta University of FlorenceEdmonton, Alberta, Canada Florence, ItalyFrancesco Masulli M. Nieto-VesperinasUniversity of Genoa Instituto de Ciencia de MaterialesGenoa, ItalyMadrid, SpainVincent P. McGinn Kenneth V. NorenNorthern Illinois UniversityUniversity of IdahoDeKalb, ILMoscow, ID 2000 by CRC Press LLC 19. Behrooz NowrouzianMarek PerkowskiUniversity of Alberta Portland State UniversityEdmonton, Alberta, Canada Portland, ORTerrence P. OConnorRoman PichnaPurdue University School of University of Oulu Technology at New Albany Oulu, FinlandNew Albany, INA. H. PiersonBen O. OniPierson Scientic Associates, Inc.Tuskegee University Andover, MATuskegee, ALPragasen PillayThomas H. OrtmeyerClarkson UniversityClarkson University Potsdam, NYPotsdam, NYAgostina PoggiRon P. OTooleUniversit d ParmaCedar Rapids, IAParma, ItalyTony Ottosson Aun Neow PooChalmers University of Technology Postgraduate School of EngineeringGteburg, SwedenNational University of SingaporeSingaporeJ. R. ParkerUniversity of Calgary Ramas RamaswamiCalgary, Alberta, CanadaMultiDisciplinary ResearchYpsilanti, MIStefan ParkvalRoyal Institute of Technology Satiskuman J. RanadeStockholm, Sweden New Mexico State UniversityLas Cruces, NMJoseph E. PascenteDowners Grove, IL Lars K. RasmussenCentre for Wireless CommunicationsRussell W. PattersonSingaporeTennessee Valley AuthorityChattanooga, TN Walter RawleEricsson, Inc.Steven PekarekLynchburg, VAUniversity of MissouriRolla, MO C. J. ReddyNASA Langley Research CenterHampton, VA 2000 by CRC Press LLC 20. Greg ReeseManfred SchindlerDayton, OHATN MicrowaveNorth Billerica, MAJoseph M. ReinhardtUniversity of IowaWarren SeelyIowa City, IA MotorolaScottsdale, AZNabeel RizaUniversity of Central Florida Yun ShiOrlando, FL New Jersey Institute of TechnologyNewark, NJJohn A. RobinsonMemorial University of Newfoundland Mikael SkoglundSt. Johns, Newfoundland, CanadaChalmers University of TechnologyGteborg, SwedenEric RogersUniversity of Southampton Rodney Daryl SloneHigheld, Southampton, EnglandUniversity of KentuckyLexington, KYChristian RonseUniversit Louis PasteurKeyue M. SmedleyStrasbourg, FranceUniversity of CaliforniaIrvine, CAPieter van RooyenUniversity of PretoriaWilliam SmithPretoria, South AfricaUniversity of KentuckyLexington, KYAhmed SaifuddinCommunication Research LabBabs SollerTokyo, JapanUniversity of Massachusetts Medical CenterWorcester, MARobert SarABB Power T & D Co., Inc. Y. H. SongCary, NCBrunel UniversityUxbridge, EnglandSimon SaundersUniversity of SurreyJanusz SosnowskiGuildford, EnglandInstitute of Computer ScienceWarsaw, PolandHelmut SchillingerIOQ Elvino SousaJena, Germany University of TorontoToronto, Ontario, Canada 2000 by CRC Press LLC 21. Philip M. SprayPieter van RooyenAmarillo, TX University of Pretoria South AfricaJoe StaudingerMotorola Jonas VasellTempe, AZChalmers University of Technology Gteborg, SwedenRoman StemprokDenton, TX John L. Volakis University of MichiganDiana StewartAnn Arbor, MIPurdue University School of Technologyat New AlbanyAnnette von JouanneNew Albany, IN Oregon State University Corvallis, ORFrancis SwartsUniversity of the WitwatersrandLiancheng WangJohannesburg, South Africa ABB Power T & D Co., Inc. Cary, NCAndrzej SwierniakSilesian Technical UniversityRonald W. WaynantGliwice, PolandFDA/CDRH Rockville, MDDaniel TabakGeorge Mason UniversityLarry WearFairfax, VASacramento, CATadashi Takagi Wilson X. WenMitsubishi Electric CorporationAI SystemsOfuna, Kamakura, Japan Talstra Labs Clayton, AustraliaJaakko TalvitieUniversity of Oulu Barry WilkinsonOulu, FinlandUniversity of North Carolina Charlotte, NCHamid A. ToliyatTexas A&M University Robert E. WilsonCollege Station, TXWestern Area Power Administration Montrose, CAAustin TruittTexas InstrumentsStacy S. WilsonDallas, TX Western Kentucky University Bowling Green, KY 2000 by CRC Press LLC 22. Denise M. WolfStanislaw H. ZakLawrence Berkeley National Laboratory Purdue UniversityBerkeley, CAWest Lafayette, INE. YazQing ZhaoUniversity of ArkansasUniversity of Western OntarioFayetteville, ArkansasLondon, Ontario, CanadaPochi Yeh Jizhong ZhuUniversity of CaliforniaNational University of SingaporeSanta Barbara, CA SingaporeJeffrey Young Omar ZiaUniversity of Idaho Marietta, GAMoscow, ID 2000 by CRC Press LLC 23. 0 common symbol for permeability of free space constant. 0 = 1.257 1016 henrys/meter. Special r ability.common symbol for relative perme-Symbolscommon symbol for radian frequency in radians/second. = 2 frequency. +common symbol for positive transition-level seta crisp set of elements belong- angle in degrees.ing to a fuzzy set A at least to a degree common symbol for negative transi- A = {x X | A (x) } tion angle in degrees.See also crisp set, fuzzy set. condcommon symbol for conduction an- gle in degrees. f common symbol for bandwidth, inhertz. satcommon symbol for saturation angle in degrees. rGaAscommon symbol for gallium ar-senide relative dielectric constant. rGaAs = CCcommon symbol for FET channel-12.8.to-case thermal resistance in C/watt. J Ccommon symbol for bipolar junction- common symbol for silicon relativerSi to-case thermal resistance in C/watt.dielectric constant. rSi = 11.8. A common symbol for Richardsons0symbol for permitivity of free space. constant. A = 8.7 amperes cm/ K0 = 8.849 1012 farad/meter. BVGD See gate-to-drain breakdownr common symbol for relative dielectricvoltage.constant. BVGS See gate-to-source breakdownDC common symbol for DC to RF con-voltage.version efciency. Expressed as a percent-age. dv/dt rate of change of voltage with- stand capability without spurious turn-on ofacommon symbol for power added ef-the device.ciency. Expressed as a percentage. HciSee intrinsic coercive force.t common symbol for total or true ef-ciency. Expressed as a percentage. ne common symbol for excess noise in watts.optcommon symbol for source reec-tion coefcient for optimum noise perfor-ns hcommon symbol for shot noise inmance. watts.c 2000 by CRC Press LLC 24. nt common symbol for thermal noise in deux indices, IRIA Rapport Laboria, No.watts.31, Sept. 1973.10base2a type of coaxial cable used to2-D FornasiniMarchesini modela 2-Dconnect nodes on an Ethernet network. The model described by the equations10 refers to the transfer rate used on standardEthernet, 10 megabits per second. The base xi+1,j +1 = A0 xi,j + A1 xi+1,jmeans that the network uses baseband com-+ A2 xi,j +1 + Buij (1a)munication rather than broadband communi-yij = Cxij + Duij (1b)cations, and the 2 stands for the maximumlength of cable segment, 185 meters (almost i, j Z+ (the set of nonnegative integers)200). This type of cable is also called thinhere xij R n is the local state vector,Ethernet, because it is a smaller diameter ca-uij R m is the input vector, yij R p isble than the 10base5 cables.the output vector Ak (k = 0, 1, 2), B, C, Dare real matrices. A 2-D model described by10base5 a type of coaxial cable used to the equationsconnect nodes on an Ethernet network. The xi+1,j +1 = A1 xi+1,j + A2 xi,j +110 refers to the transfer rate used on stan-dard Ethernet, 10 megabits per second. The + B1 ui+1,j + B2 ui,j +1 (2)base means that the network uses basebandi, j Z+ and (1b) is called the second 2-Dcommunication rather than broadband com-FornasiniMarchesini model, where xij , uij ,munications, and the 5 stands for the max-and yij are dened in the same way as for (1),imum length of cable segment of approxi-Ak , Bk (k = 0, 1, 2) are real matrices. Themately 500 meters. This type of cable is alsomodel (1) is a particular case of (2).called thick Ethernet, because it is a largerdiameter cable than the 10base2 cables.2-D general modela 2-D model de-scribed by the equations10baseTa type of coaxial cable used toconnect nodes on an Ethernet network. The xi+1,j +1 = A0 xi,j + A1 xi+1,j10 refers to the transfer rate used on standard + A2 xi,j +1 + B0 uijEthernet, 10 megabits per second. The basemeans that the network uses baseband com- + B1 ui+1,j + B2 ui,j +1munication rather than broadband communi- yij = Cxij + Duijcations, and the T stands for twisted (wire)cable.i, j Z+ (the set of nonnegative integers)here xij R n is the local state vector, uij 2-D Attasi modela 2-D model described R m is the input vector, yij R p is the outputby the equationsvector and Ak , Bk (k = 0, 1, 2), C, D are realmatrices. In particular case for B1 = B2 = 0 xi+1,j +1 = A1 A2 xi,j + A1 xi+1,jwe obtain the rst 2-D FornasiniMarchesinimodel and for A0 = 0 and B0 = 0 we obtain + A2 xi,j +1 + Buijthe second 2-D FornasiniMarchesini model. yij = Cxij + Duij2-D polynomial matrix equation a 2-Di, j Z+ (the set of nonnegative integers).equation of the formHere xij R n is the local state vector,uij R m is the input vector, yij R p isAX + BY = C (1)the output vector, and A1 , A2 , B, C, D arereal matrices. The model was introduced bywhere A R kp [s], B R kq [s], C Attasi in Systemes lineaires homogenes a R km [s] are given, by a solution to (1) wec 2000 by CRC Press LLC 25. mean any pair X R pm [s], Y R qm [s]The algorithm is based on the row compres-satisfying the equation. The equation (1) sion of suitable matrices.has a solution if and only if the matrices[A, B, C] and [A, B, 0] are column equiva-2-D Z-transform F (z1 , z2 ) of a dis-lent or the greatest common left divisor of A crete 2-D function fij satisfying the condi-and B is a left divisor of C. The 2-D equationtion fij = 0 for i < 0 or/and j < 0 isdened by AX + Y B = C (2) i jA R kp[s], B R qm [s], C R km [s] F (z1 , z2 ) =fij z1 z2are given, is called the bilateral 2-D polyno- i=0 j =0mial matrix equation. By a solution to (2) we An 2-D discrete fij has the 2-D Z-transformmean any pair X R pm [s], Y R kq [s]if the sumsatisfying the equation. The equation has a solution if and only if the matrices ijfij z1 z2 i=0 j =0 A 0AC and 0 B0 B exists.are equivalent. 2DEGFETSee high electron mobilitytransistor(HEMT).2-D Roesser modela 2-D model de-scribed by the equations2LG See double phase ground fault.h xi+1,jh A1 A2xij B13-dB bandwidthfor a causal low-pass = + uv xi,j +1 A3 A4 vxij B2 ij or bandpass lter with a frequency functioni, j Z+ (the set of nonnegative integers),H (j ) the frequency at which | H (j ) |dBis less than 3 dB down from the peak value hxij | H (P ) |. yij = C v+ Duijxij3-level lasera laser in which the mosthvHere xij R n1 and xij R n2 are the hori-important transitions involve only three en-zontal and vertical local state vectors, respec-ergy states; usually refers to a laser in whichtively, uij R m is the input vector, yij R pthe lower level of the laser transition is sepa-is the output vector and A1 , A2 , A3 , A4 , B1 , rated from the ground state by much less thanB2 , C, D are real matrices. The model wasthe thermal energy kT. Contrast with 4-levelintroduced by R.P. Roesser in A discrete laser.state-space model for linear image process-ing, IEEE Trans. Autom. Contr., AC-20, 3-level system a quantum mechanicalNo. 1, 1975, pp. 1-10.system whose interaction with one or moreelectromagnetic elds can be described by2-D shufe algorithm an extension of theconsidering primarily three energy levels.Luenberger shufe algorithm for 1-D case. For example, the cascade, vee, and lambdaThe 2-D shufe algorithm can be used forsystems are 3-level systems.checking the regularity condition4-level lasera laser in which the most det [Ez1 z2 A0 A1 z1 A2 z2 ] = 0 important transitions involve only four en-ergy states; usually refers to a laser in whichfor some (z1 , z2 ) CC of the singular gen-the lower level of the laser transition is sep-eral model ( See singular 2-D general model). arated from the ground state by much morec 2000 by CRC Press LLC 26. than the thermal energy kT . Contrast with ty of the image. For example a leak factor of 313-level laser. 32 the prediction decay is maintained at the center of the dynamic range.45 Mbs DPCM for NTSC color videoa codec wherein a subjectively pleasing pic- 31 ture is required at the receiver. This doesXL = 128 +X 128 .not require transparent coding quality typical32of TV signals. The output bit-rate for video Finally, a clipper at the coder and decodermatches the DS3 44.736 Megabits per second is employed to prevent quantization errors.rate. The coding is done by PCM coding theNTSC composite video signal at three times 90% withstand voltagea measure ofthe color subcarrier frequency using 8 bit per the practical lightning or switching-surge im-pixel. Prediction of current pixel is obtained pulse withstand capability of a piece of powerby averaging the pixel three after current and equipment. This voltage withstand level is681 pixels before next to maintain the sub-two standard deviations above the BIL of thecarrier phase. A leak factor is chosen beforeequipment.computing prediction error to main the quali-c 2000 by CRC Press LLC 27. two-port networks. Sometimes referred toas chain parameters. ABCD parameters are Awidely used to model cascaded connectionsof two-port microwave networks, in whichcase the ABCD matrix is dened for eachtwo-port network. ABCD parameters canalso be used in analytic formalisms for prop-a posteriori probability See posterioragating Gaussian beams and light rays. Raystatistics. matrices and beam matrices are similar butare often regarded as distinct.a priori probabilitySee prior statistics.ABC parameters have a particularly use-ful property in circuit analysis where theA-mode displayreturned ultrasound composite ABCD parameters of two cas-echoes displayed as amplitude versus depthcaded networks are the matrix products ofinto the body.the ABCD parameters of the two individualcircuits. ABCD parameters are dened asA-site in a ferroelectric material with thechemical formula ABO3 , the crystalline lo- v1AB v2 =cation of the A atom. i1CD i2A/DSee analog-to-digital converter. where v1 and v2 are the voltages on ports oneand two, and i1 and i2 are the branch currentsAAL See ATM adaptation layer. into ports one and two.ABC See absorbing boundary condition. aberration an imperfection of an opticalsystem that leads to a blurred or a distortedABCD propagation of an optical rayimage.through a system can be described by a sim-ple 22 matrix. In ray optics, the character- abnormal event any external or program-istic of a system is given by the correspond- generated event that makes further normaling ray matrix relating the rays position from program execution impossible or undesir-the axis and slope at the input to those at the able, resulting in a system interrupt. Exam-output. ples of abnormal events include system de-tection of power failure; attempt to divide byABCD formalism analytic method using0; attempt to execute privileged instructiontwo-by-two ABCD matrices for propagatingwithout privileged status; memory parity er-Gaussian beams and light rays in a wide va- ror.riety of optical systems.abort (1) in computer systems, to termi-ABCD law analytic formula for trans-nate the attempt to complete the transaction,forming a Gaussian beam parameter fromusually because there is a deadlock or be-one reference plane to another in paraxial op-cause completing the transaction would re-tics, sometimes called the Kogelnik transfor- sult in a system state that is not compati-mation. ABCD refers to the ABCD matrix. ble with correct behavior, as dened by aconsistency model, such as sequential con-ABCD matrix the matrix containing sistency.ABCD parameters. See ABCD parameters. (2) in an accelerator, terminating the ac-celeration process prematurely, either by in-ABCD parameters a convenient mathe- hibiting the injection mechanism or by re-matical form that can be used to characterize moving circulating beam to some sort ofc 2000 by CRC Press LLC 28. dump. This is generally done to prevent in- absolute sensitivity denoted S(y, x), isjury to some personnel or damage to acceler-simply the partial derivative of y with respectator components.to x, i.e., S(y, x) = y/x, and is used toestablish the relationships between absoluteABR See available bit rate. changes. See sensitivity, sensitivity measure,relative sensitivity, semi-relative sensitivity.absolute addressan address within aninstruction that directly indicates a location in absolute stabilityoccurs when the net-the programs address space. Compare with work function H (s) has only left half-planerelative addressing.poles.absolute addressingan addressing mode absorbergeneric term used to describewhere the address of the instruction operandmaterial used to absorb electromagnetic en-in memory is a part of the instruction so thatergy. Generally made of polyurethaneno calculation of an effective address by the foam and impregnated with carbon (and re-CPU is necessary. retardant salts), it is most frequently used to For example, in the Motorola M68000 ar-line the walls, oors and ceilings of anechoicchitecture instruction ADD 5000,D1, a 16-bitchambers to reduce or eliminate reectionsword operand, stored in memory at the wordfrom these surfaces.address 5000, is added to the lower word inregister D1. The address 5000 is an exam- absorbing boundary condition (ABC)aple of using the absolute addressing mode.ctitious boundary introduced in differentialSee also addressing mode. equation methods to truncate the computa-tional space at a nite distance without, inabsolute encoder an optical deviceprinciple, creating any reections.mounted to the shaft of a motor consistingof a disc with a pattern and light sources andabsorption (1) process that dissipates en-detectors. The combination of light detectors ergy and causes a decrease in the amplitudereceiving light depends on the position of theand intensity of a propagating wave betweenrotor and the pattern employed (typically the an input and output reference plane.Gray code). Thus, absolute position infor-(2) reduction in the number of photons of amation is obtained. The higher the resolution specic wavelength or energy incident uponrequired, the larger the number of detectorsa material. Energy transferred to the materialneeded. See also encoder. may result in a change in the electronic struc-ture, or in the relative movement of atoms inabsolute moment The pth order absolutethe material (vibration or rotation).moment p of a random variable X is the (3) process by which atoms or moleculesexpectation of the absolute value of X raised stick to a surface. If a bond is formed, it isto the pth power: termed chemisorption, while the normal caseis physisorption. The absorption process pro- p = E[|X|]p . ceeds due to, and is supported by, the fact thatthis is a lower energy state.See also central moment, central absolutemoment. See also expectation. absorption coefcient (1) in a passive de-vice, the negative ratio of the power absorbedabsolute pressureunits to measure gas (pabsorbed = pin pout ) ratioed to the power inpressure in a vacuum chamber with zero be-(pin = pincident preected ) per unit length (l),ing a perfect vacuum. Normally referred tousually expressed in units of 1/wavelength oras psia (pounds per square inch absolute).1/meter.c 2000 by CRC Press LLC 29. (2) factor describing the fractional atten- rameter are closest to the parameters of anuation of light with distance traversed in aideal capacitor. Hence, not only a capaci-medium, generally expressed as an exponen-tance is measured in terms of capacitance (intial factor, such as k in the function ekx , resistive ratio arms bridges), but the induc-with units of (length)-1. Also called attenu- tance as well is measured in terms of capac-ation coefcient. itance (Hay and Owen bridges). The AC bridges with ratio arms that areabsorption cross section energy ab- tightly coupled inductances allow measure-sorbed by the scattering medium, normal-ment of a very small difference between cur-ized to the wavenumber. It has dimensions rents in these inductances, and this fact isof area.used in very sensitive capacitance transduc-ers.absorption edgethe optical wavelengthor photon energy corresponding to the sep-AC circuit electrical network in which thearation of valence and conduction bands involtage polarity and directions of current owsolids; at shorter wavelengths, or higher pho-change continuously, and often periodically.ton energies than the absorption edge, the ab-Thus, such networks contain alternating cur-sorption increases strongly.rents as opposed to direct currents, therebygiving rise to the term.absorption grating(1) a diffractiongrating where alternate grating periods areAC coupling a method of connecting twoopaque.circuits that allows displacement current to (2) an optical grating characterized byow while preventing conductive currents.spatially periodic variation in the absorptionReactive impedance devices (e.g., capacitorsof light. Absorption gratings are generally and inductive transformers) are used to pro-less efcient than phase gratings.vide continuity of alternating current owbetween two circuits while simultaneouslyabsorption optical ber the amount of blocking the ow of direct current.optical power in an optical ber capturedby defect and impurity centers in the energyAC motor an electromechanical sys-bandgap of the ber material and lost in thetem that converts alternating current electri-form of longwave infrared radiation.cal power into mechanical power.ACSee alternating current.AC plasma displaya display that em-AC bridgeone of a wide group of ploys an internal capacitive dielectric layerbridge circuits used for measurements of re-to limit the gas discharge current.sistances, inductances, and capacitances, andto provide AC signal in the bridge transducersAC steady-state powerthe averageincluding resistors, inductors, and capacitors. power delivered by a sinusoidal source to aThe Wheatstone bridge can be used withnetwork, expressed asa sinusoidal power supply, and with an ACdetector (headphones, oscilloscope), one can P =| V | | I | cos( )use essentially the same procedure for mea-surement of resistors as in DC applications.where 2 | V | and 2 | I | are the peakOnly a small number of other AC bridges are values, respectively, of the AC steady-stateused in modern electric and electronic equip- voltage and current at the terminals. rep-ment. A strong selection factor was the factresents the phase angle by which the voltagethat in a standard capacitor the electrical pa- leads the current.c 2000 by CRC Press LLC 30. AC/AC converter a power electronics ation error to a constraint on the gain of thedevice in which an AC input voltage of some open loop system. The relevant equationsmagnitude, frequency, and number of phasesare ea = Ka and Ka = limsinf ty s 2 q(s),1is changed to an AC output with changes towhere q(s) is the transfer function modelany of the previously mentioned parameters. of the open loop system, including the con-AC/AC converters usually rectify the inputtroller and the process in cascade, and s issource to a DC voltage and then invert thethe Laplace variable. See also position errorDC voltage to the desired AC voltage. constant, velocity error constant.AC/DC converter See rectier. accelerator(1) a positive electrode in avacuum tube to accelerate emitted electronsAC-DC integrated system a power sys-from its cathode by coulomb force in a de-tem containing both AC and DC transmissionsired direction.lines. (2) a machine used to impart large kineticenergies to charged particles such as elec-ACARSaircraft communications ad-trons, protons, and atomic nuclei. The ac-dressing and reporting. A digital commu-celerated particles are used to probe nuclearnications link using the VHF spectrum for or subnuclear phenomena in industrial andtwo-way transmission of data between an air-medical applications.craft and ground. It is used primarily in civilaviation applications.acceptable delay the voice signal de-lay that results in inconvenience in the voiceACC See automatic chroma control.communication. A typically quoted value is300 ms.accelerated testing tests conducted athigher stress levels than normal operation butacceptancein an accelerator, it denesin a shorter period of time for the specichow "large" a beam will t without scrap-purpose to induce failure faster.ing into the limiting aperture of a transportline. The acceptance is the phase-space vol-accelerating powerthe excess electricume within which the beam must lie to bepower at a synchronous machine unit whichtransmitted through an optical system with-cannot be transmitted to the load because ofout losses. From an experimenters pointa short circuit near its terminals. This energyof view acceptance is the phase-space vol-gives rise to increasing rotor angle.ume intercepted by an experimenters detec-tor system.acceleration error the nal steady dif-ference between a parabolic setpoint and theprocess output in a unity feedback controlacceptor(1) an impurity in a semicon-system. Thus it is the asymptotic error in po-ductor that donates a free hole to the valencesition that arises in a closed loop system that band.is commanded to move with constant acceler-(2) a dopant species that traps electrons,ation. See also position error, velocity error. especially with regard to semiconductors.acceleration error constanta gain Kaaccess channela channel in a communi-from which acceleration error ea is read- cations network that is typically allocated forily determined. The acceleration error con- the purpose of setting up calls or communi-stant is a concept that is useful in the design cation sessions. Typically the users share theof unity feedback control systems, since it access channel using some multiple accesstransforms a constraint on the nal acceler-algorithm such as ALOHA or CSMA.c 2000 by CRC Press LLC 31. access control a means of allowing ac-time until the desired data rotates under thecess to an object based on the type of ac-head. (LW)cess sought, the accessors privileges, and theowners policy.accidental ratethe rate of false coinci-dences in the electronic counter experimentaccess control list a list of items associ-produced by products of the reactions of moreated with a le or other object; the list con-than one beam particle within the time reso-tains the identities of users that are permittedlution of the apparatus.access to the associated le. There is infor-mation (usually in the form of a set of bits)about the types of access (such as read, write, accumulation (1) an increase in the ma-or delete) permitted to the user. jority carrier concentration of a region ofsemiconductor due to an externally appliedaccess control matrix a tabular repre-electric eld.sentation of the modes of access permittedfrom active entities (programs or processes)accumulator (1) a register in the CPUto passive entities (objects, les, or devices).(processor) that stores one of the operandsA typical format associates a row with an ac- prior to the execution of an operation, andtive entity or subject and a column with an into which the result of the operation isobject; the modes of access permitted fromstored. An accumulator serves as an implicitthat active entity to the associated passive en-source and destination of many of the pro-tity are listed in the table entry. cessor instructions. For example, register Aof the Intel 8085 is an accumulator. See alsoaccess line a communication line that CPU .connects a users terminal equipment to aswitching node. (2) the storage ring in which successivepulses of particles are collected to create aaccess mechanism a circuit board or anparticle beam of reasonable intensity for col-integrated chip that allows a given part of a liding beams.computer system to access another part. Thisis typically performed by using a specic ac- achievable rate region for a multiplecess protocol.terminal communications system, a set ofrate-vectors for which there exist codes suchaccess protocol a set of rules that estab-that the probability of making a decoding er-lishes communication among different parts. ror can be made arbitrarily small. See alsoThese can involve both hardware and soft- capacity region, multiple access channel.ware specications.access rightpermission to perform anachromatic the quality of a transport lineoperation on an object, usually specied as or optical system where particle momentumthe type of operation that is permitted, such has no effect on its trajectory through the sys-as read, write, or delete. Access rights cantem. In an achromatic device or system, thebe included in access control lists, capability output beam displacement or divergence (orlists, or in an overall access control matrix.both) is independent of the input beams mo-mentum. If a system of lenses is achromatic,access timethe total time needed to re- all particles of the same momentum will havetrieve data from memory. For a disk drive equal path lengths through the system.this is the sum of the time to position theread/write head over the desired track and theACISee adjacent channel interference.c 2000 by CRC Press LLC 32. acknowledge(1) a signal which indicates another signal in a second cell, or with xedthat some operation, such as a data transfer, signals on a mask.has successfully been completed. (2) to detect the successful completion of acousto-optic deector device devicean operation and produce a signal indicatingwhere acousto-optic interaction deects thethe success.incident beam linearly as a function of theinput frequency of the RF signal driving theacoustic attenuationthe degree of am- device.plitude suppression suffered by the acous-tic wave traveling along the acousto-opticacousto-optic devicedescriptor ofmedium. acousto-optic cells of any design; generallydescribes a cell plus its transducer struc-acoustic lasera laser (or maser) in which ture(s), and may encompass either bulk,the amplied eld consists of soundwaves or guided-wave, or ber-optic devices.phonons rather than electromagnetic waves;phonon laser or phaser. acousto-optic effect the interaction oflight with sound waves and in particular theacoustic memory a form of circulating modication of the properties of a light wavememory in which information is encoded in by its interactions with an electrically con-acoustic waves, typically propagated throughtrollable sound wave. See also Brillouina trough of mercury. Now obsolete.scattering.acoustic velocitythe velocity of theacousto-optic frequency excisorsimilaracoustic signal traveling along the acousto-to an acousto-optic spectrum analyzer whereoptic medium.the RF temporal spectrum is spatially and se-lectively blocked to lter the RF signal feed-acoustic wave a propagating periodicing the Bragg cell.pressure wave with amplitude representingeither longitudinal or shear particle displace-ment within the wave medium; shear wavesacousto-optic instantaneous spectrum an-are prohibited in gaseous and liquid media. alyzer in Bragg mode device in which thetemporal spectrum of a radio frequency sig-acousto-optic cell a device consisting of nal is instantaneously and spatially resolveda photo-elastic medium in which a propa-in the optical domain using a Fourier trans-gating acoustic wave causes refractive-indexform lens and a RF signal-fed Bragg cell.changes, proportional to acoustic wave am-plitude, that act as a phase grating for diffrac- acousto-optic modulatora device thattion of light. See also Bragg cell. modies the amplitude or phase of a lightwave by means of the acousto-optic effect.acousto-optic channelized radiometerSee acousto-optic instantaneous spectrumacousto-optic processor an optical sys-analyzer in Bragg mode. tem that incorporates acousto-optic cells con-gured to perform any of a number of math-acousto-optic correlator an optical sys-ematical functions such as Fourier trans-tem that consists of at least one acousto-form, ambiguity transforms, and other time-optic cell, imaging optics between cells andfrequency transforms.xed masks, and photodetectors whose out-puts correspond to the correlation function ofacousto-optic scannera device that usesthe acoustic wave signal within one cell with an acoustic wave in a photoelastic mediumc 2000 by CRC Press LLC 33. to deect light to different angular positionsacousto-opticsthe area of study of in-based on the frequency of the acoustic wave.teraction of light and sound in media, andits utilization in applications such as signalacousto-optic space integrating convolver processing and ltering. device that is the same as an acousto-opticspace integrating convolver except that it im-ACP See adjacent channel power.plements the convolution operation.acquisition (1) in digital communica-acousto-optic space integrating correlatortions systems, the process of acquiring syn- an acousto-optic implementation of the cor-chronism with the received signal. Thererelation function where two RF signals areare several levels of acquisitions, and for aspatially impressed on two diffracted beams given communication system several of themfrom Bragg cells, and a Fourier transform have to be performed in the process of settinglens spatially integrates these beams onto aup a communication link: frequency, phase,point sensor that generates a photo current spreading code, symbol, frame, etc.representing the correlation function. (2) in analog communications systems,the process of initially estimating signal pa-acousto-optic spectrum analyzeran rameters (for example carrier frequency off-acousto-optic processor that produces at aset, phase offset) required in order to beginphotodetector output array the Fourier de-demodulation of the received signal.composition of the electrical drive signal of(3) in vision processing, the process byan acousto-optic device.which a scene (physical phenomenon) isconverted into a suitable format that al-lows for its storage or retrieval. See alsoacousto-optic time integrating convolversynchronization. same as the acousto-optic time integratingcorrelator, except implements the signal con-across the line starter a motor starter thatvolution operation. See acousto-optic timeapplies full line voltage to the motor to start.integrating correlator.This is also referred to as hard starting be-cause it causes high starting currents. Largeracousto-optic time integrating correlator motors require reduced voltage or soft start- an acousto-optic implementation of the cor-ing.relation function where two RF signals arespatially impressed on two diffracted beams ACRRSee adjacent channel reuse ratio.from Bragg cells, and a time integrating sen-sor generates the spatially distributed corre-ACSRaluminum cable, steel-reinforced.lation results. A kind of overhead electric power conduc-tor made up of a central stranded steel cableacousto-optic triple product processoroverlaid with strands of aluminum.signal processor that implements a triple inte-gration operation using generally both spaceACT See anticomet tail.and time dimensions.action potential a propagating change inacousto-optic tunable lter (AOTF) an the conductivity and potential across a nerveacousto-optic device that selects specic op- cells membrane; a nerve impulse in commontical frequencies from a broadband opticalparlance.beam, depending on the number and frequen-cies of acoustic waves generated in the de- activation function in an articial neuralvice. network, a function that maps the net outputc 2000 by CRC Press LLC 34. of a neuron to a smaller set of values. Thisactive loada transistor connected so as toset is usually [0, 1]. Typical functions are thereplace a function that would conventionallysigmoid function or singularity functions likebe performed by a passive component suchthe step or ramp. as a resistor, capacitor, or inductor.active contour a deformable templateactive load-pull measurementa mea-matching method that, by minimizing the surement method where transfer characteris-energy function associated with a specic tics of a device can be measured by electri-model (i.e., a specic characterization of thecally changing the load impedance seen fromshape of an object), deforms the model in the device. In an active load-pull measure-conformation to salient image features. ment, the load impedance is dened by usingan output signal from the device and an in-jected signal from the output of the device.active device a device that can convertenergy from a DC bias source to a signal atactive logic a digital logic that operatesan RF frequency. Active devices are requiredall of the time in the active, dissipative regionin oscillators and ampliers.of the electronic ampliers from which it isconstructed. The output of such a gate isactive lter(1) a lter that has an en- determined primarily by the gate and not byergy gain greater than one, that is, a lter that the load.outputs more energy than it absorbs. (2) a form of power electronic converter active magnetic bearinga magneticdesigned to effectively cancel harmonic cur-bearing that requires input energy for stablerents by injecting currents that are equal andsupport during operation. Generally imple-opposite to, or 180 out of phase with, the tar-mented with one or more electromagnets andget harmonics. Active lters allow the out- controllers.put current to be controlled and provide sta-ble operation against AC source impedance active mixer a mixer that uses three termi-variations without interfering with the systemnal devices such as FET rather than diodes asimpedance.nonlinear element. One advantage of active The main type of active lter is the seriesmixers is that they can provide conversiontype in which a voltage is added in series with gain.an existing bus voltage. The other type is theparallel type in which a current is injectedactive network an electrical networkinto the bus and cancels the line current har-that contains some solid state devices such asmonics. bipolar junction transistors (BJTs) or metal-oxide-silicon eld effect transistors (FETs)operating in their active region of the volt-active impedancethe impedance at theage vs. current characteristic. To ensure thatinput of a single antenna element of an ar-these devices are operating in the active re-ray with all the other elements of the arraygion, they must be supplied with proper DCexcited.biasing.active layerSee active region.active neuron a neuron with a non-zerooutput. Most neurons have an activationactive learning a form of machine learn-threshold. The output of such a neuron hasing where the learning system is able to in-zero output until this threshold is reached.teract with its environment so as to affect thegeneration of training data.active power See real power.c 2000 by CRC Press LLC 35. active power line conditioner a deviceACTV See advanced compatible tele-which senses disturbances on a power line vision.and injects compensating voltages or currentsto restore the lines proper waveform.acuitysharpness. The ability of the eyeto discern between two small objects closelyactive RC lter an electronic circuit spaced, as on a display.made up of resistors, capacitors, and opera-tional ampliers that provide well-controlled adaptability the capability of a system tolinear frequency-dependent functions, e.g., change to suit the prevailing conditions, espe-low-, high-, and bandpass lters. cially by automatic adjustment of parametersthrough some initialization procedure or byactive redundancy a circuit redundancytraining.technique that assures fault-tolerance by de-adaptation layercontrol layer of a mul-tecting the existence of faults and performingtilayer controller, situated above the directsome action to remove the faulty hardware,control layer and usually also above thee.g., by standby sparing.optimizing control layer, required to intro-duce changes into the decision mechanismsactive regionsemiconductor material of the layer (or layers) below this adaptationdoped such that electrons and/or holes arelayer; for example adaptation layer of the in-free to move when the material is biased. Industrial controller may be responsible for ad-the nal fabricated device, the active regionsjusting the model used by the optimizing con-are usually conned to very small portions of trol and the decision rules used by the directthe wafer material. (regulation) control mechanisms.active-high (1) a logic signal having its adaptera typical term from personalasserted state as the logic ONE state.computers. A circuit board containing the (2) a logic signal having the logic ONEinterface toward an additional peripheral de-state as the higher voltage of the two states.vice. For example, a graphic adapter (inter-face boards like EGA, VGA, CGA), a gameactive-low (1) a logic signal having itscontroller, a SCSI controller, a PCMCI inter-asserted state as the logic ZERO state. face, etc. (2) a logic signal having its logic ONEadaptive algorithm (1) a method for ad-state as the lower voltage of the two states;justing the parameters of a lter to satisfy aninverted logic.objective (e.g., minimize a cost function). (2) an algorithm whose properties are ad-actuator(1) a transducer that convertsjusted continuously during execution withelectrical, hydraulic, or pneumatic energy to the objective of optimizing some criterion.effective motion. For example in robots, ac-tuators set the manipulator in motion through adaptive antennaantenna, or array ofactuation of the joints. Industrial robotsantennas, whose performance characteristicsare equipped with motors that are typically can be adapted by some means; e.g., theelectric, hydraulic, or pneumatic. See also pattern of an array can be changed whenindustrial robot. the phasing of each of the array elements is (2) in computers, a device, usually me-changed.chanical in nature, that is controlled by acomputer, e.g., a printer paper mechanism oradaptive arrayan array that adapts itselfa disk drive head positioning mechanism.to maximize the reception of a desired sig-c 2000 by CRC Press LLC 36. nal and null all interfering or jamming sig- adaptive FIR lter a nite impulse re-nals. This is achieved by nding the correct sponse structure lter with adjustable coef-weights (input excitations) to the elementscients. The adjustment is controlled by ancomprising the array.adaptation algorithm such as the least mean square (LMS) algorithm. They are usedadaptive coding a coding scheme that extensively in adaptive echo cancellers andadapts itself in some fashion to its input orequalizers in communication systems.output. adaptive fuzzy systemfuzzy inferenceadaptive coding of transform coefcients system that can be trained on a data setcoding technique that is carried out bythrough the same learning techniques usedthreshold sampling and exploiting maskingfor neural networks. Adaptive fuzzy systemseffects by variable quantization for differ- are able to incorporate domain knowledgeent blocks. High detail blocks are coded about the target system given from humanwith more quantization error than low de-experts in the form of fuzzy rules and numer-tail blocks. This is done to take into ac- ical data in the form of inputoutput data setscount masking and boundary distortion ef-of the system to be modeled. See also neuralfects. Transform coding becomes more at- network, fuzzy inference system.tractive compared with DPCM when adap-tive coding is used. The main drawback ofadaptive intraeld predictors a tech-adaptive transform coding is its sensitivity nique used for picture signal prediction basedto transmission bit errors due to synchro- on local properties of the signal or side infor-nization problems at the decoder. See also mation if portions of local properties haveDPCM.not been transmitted. Intraeld methods re- quire correlation with local information foradaptive control a control methodology prediction purposes.in which control parameters are continuouslyA common technique is to use a mea-and automatically adjusted in response tosure of the directional correlation based onbe measured/estimated process variables to local pixels that have already been transmit-achieve near-optimum system performance. ted. A predictor is chosen from a set to give minimum prediction error. For example, theadaptive critic learning technique where previous line or previous pixel can be usedthe system learns to evaluate the actions of a for prediction, and the switching can then besystem (usually a controller) so as to provide done as follows:a reinforcement signal that is an estimate ofthe future value of the systems current ac-tion. X = predictor for element XA if B C < A B =adaptive differential pulse code modula-C otherwisetion (ADPCM)a modulation scheme inwhich only the difference between successive An extension of this concept is called con-signal samples is encoded for transmission,tour prediction where the direction of pixel Aand the quantization of the coding is adaptedis determined by searching among E, B, C,to the characteristics of the signal source. or G.adaptive lteringa ltering strategy inadaptive logic networktree-structuredwhich lter coefcients or governing param-network whose leaves are the inputs andeters evolve over time according to some up- whose root is the output. The rst hiddendating strategy to optimize some criterion.layer consists of linear threshold units and thec 2000 by CRC Press LLC 37. remaining layers are elementary logic gates,the new pattern is added to that prototypesusually AND and OR gates. Each linear cluster and the prototype is adjusted so asthreshold unit is trained to t input data in to move closer to the new input. If no pro-those regions of the input space where it istotype is acceptable, the pattern becomes aactive (i.e., where it contributes to the overall new prototype around which a new clusternetwork function).may develop.adaptive manipulator controller a con-adaptive vector quantizationterm thattroller that uses an adaptation process which,refers to methods for vector quantization thatbased on observation of the manipulator po- are designed to adaptively track changes insition and velocity, readjusts the parameters the input signal.in the nonlinear model until the errors dis-appear. An adaptive manipulator controllerADC See analog-to-digital converter.is depicted in the gure below. Such a sys-tem would learn its own dynamic properties. ADCPM See adaptive differential pulseThe adaptive manipulator control scheme code modulation.add instructiona machine instructionthat causes two numeric operands to be addedtogether. The operands may be from machineregisters, memory, or from the instruction it-self, and the result may be placed in a ma-chine register or in memory.addera logic circuit used for adding bi-nary numbers.Adaptive manipulator control scheme.additive acousto-optic processingacousto-optic signal processing where thepresented in the gure belongs to the jointsummation of acousto-optic modulated lightspace control schemes. See also joint spacewaves is used to implement the signal pro-control.cessing operation.adaptive predictor a digital lter whoseadditive polarity polarity designation ofcoefcients can be varied, according to somea transformer in which terminals of the sameerror minimization algorithm, such that it canpolarity on the low- and high-voltage coilspredict the value of a signal say N samplingare physically adjacent to each other on thetime intervals into the future. The adaptivetransformer casing. With additive polarity, apredictor is useful in many interference can- short between two adjacent terminals resultscellation applications. in the sum of the two coil voltages appearingbetween the remaining terminals. Additiveadaptive resonance theory (ART) network polarity is generally used for transformers up A clustering network developed to allow theto 500kVA and 34.5kV. Larger units use sub-learning of new information without destroy-tractive polarity. See the diagram below. Seeing what has already been learnt. Each clus-also subtractive polarity.ter is represented by a prototype and learningis achieved by comparing a new input pat- additive white Gaussian noise (AWGN)tern with each prototype. If a prototype is the simplest form of channel degradation infound that is acceptably close to that input, a communication system in which the sourcec 2000 by CRC Press LLC 38. 2. A full decoder takes N bits and assertsone of 2N outputs, and is used within mem-ories (often within RAM chips themselves).address erroran exception (error inter-rupt) caused by a programs attempt to accessunaligned words or long words on a proces-Transformer with additive polarity. sor that does not accommodate such requests.The address error is detected within the CPU.of errors in the channel can be modeled asThis contrasts with problems that arise in ac-the addition of random noise with a Gaus- cessing the memory itself, where a logic cir-sian distribution and a constant (white) powercuit external to the CPU itself must detect andspectrum. See also thermal noise. signal the error to cause the CPU to processthe exception. Such external problems areaddress a unique identier for the placecalled bus errors.where information is stored (as opposed tothe contents actually stored there). Most stor- address eld the portion of a programage devices may be regarded by the user as ainstruction word that holds an address.linear array, such as bytes or words in RAMor sectors on a disk. The address is then justaddress generation interlock (AGI)aan ordinal number of the physical or logicalmechanism to stall the pipeline for one cycleposition. In some disks, the address may be when an address used in one machine cyclecompound, consisting of the cylinder or track is being calculated or loaded in the previousand the sector within that cylinder.cycle. Address generation interlocks cause In more complex systems, the address the CPU to be delayed for a cycle. (AGIsmay be a name that is more relevant to theon the Pentium are even more important touser but must be translated by the underlying remove, since two execution time slots aresoftware or hardware. lost).address aliasingSee cache aliasing. address lockinga mechanism to protecta specic memory address so that it can beaddress busthe set of wires or tracks accessed exclusively by a single processor.on a backplane, printed circuit board, or in-tegrated circuit to carry binary address sig- address map a table that associates a basenals between different parts of a computer. address in main memory with an object (orThe number of bits of address bus (the widthpage) number.of the bus) determines the maximum size ofmemory that can be addressed. Modern mi-address mapping the translation of vir-crochips have 32 address lines, thus 4 giga-tual address into real (i.e., physical) ad-bytes of main memory can be accessed. dresses for memory access. See also virtualmemory.address decoderlogic that decodes anaddress.address register a register used primarily 1. A partial decoder responds to a small to hold the address of a location in memory.range of addresses and is used when recog-The location can contain an operand or annizing particular device addresses on an I/Oexecutable instruction.address bus, or when recognizing that ad-dresses belong to a particular memory mod-address size prex a part of a machineule.instruction that provides information as to thec 2000 by CRC Press LLC 39. length or size of the address elds in the in- addressing rangenumbers that denestruction. the number of memory locations addressable by the CPU. For a processor with one addressaddress space an area of memory seen orspace, the range is determined by the numberused by a program and generally managed as of signal lines on the address bus of the CPU.a continuous range of addresses. Many com-puters use separate address spaces for codeadequate service in terms of the block-and data; some have other address spaces ing probability, term associated with a xedfor system. An address space is usually sub- blocking. A typically quoted value may beject to protection, with references to a space 2. See also blocking.checked for valid addresses and access (suchas read only). adiabatic a system that has no heat trans- fer with the environment. The physical address space of a computer(232 bytes, and up to 264 bytes) is often larger adiabatic cooling a process where thethan the installed memory. Some parts of the temperature of a system is reduced withoutaddress range (often at extreme addresses) any heat being exchanged between the sys-may be reserved for inputoutput device ad-tem and its surroundings. In particle beamdresses. See also byte, memory, memory acceleration this term is used to describe themapped I/O.process in the particle source storage ring where beam emittances are reduced withoutaddress translation See address mapping. affecting beam energy. adiabatic following an approximationaddressing(1) in processors: a mecha-made when some states in a quantum me-nism to refer to a device or storage location by chanical system respond to perturbationsan identifying number, character, or group ofmore quickly than the other states. In thischaracters. That may contain a piece of data approximation the rapidly responding statesor a program step. are assumed to depend only on the instanta- neous values of the other states and are said (2) in networks, the process of identify- to follow those states.ing a network component, for instance, theunique address of a node on a local area net- adiabatic passage a technique for the cre-work. ation of a long-lived coherence in a quantum mechanical system by manipulating electro-addressing faultan error that halts themagnetic eld intensities so that the systemmapper when it cannot locate a referencedalways remains in an eigenstate. In practice,object in main memory. this involves changing eld strengths on a time scale slower than the inverse of the en-addressing modea form of specifyingergy spacing between relevant eigenstates ofthe address (location) of an operand in an the system. For example, consider a lambdainstruction. Some of the addressing modessystem in which only one eld is present ini-found in most processors are direct or registertially and all population starts out in the un-direct, where the operand is in a CPU register;coupled ground state. If a eld is graduallyregister indirect (or simply indirect), whereturned on to couple this initial state to the ex-a CPU register contains the address of the cited state, the system can remain transparentoperand in memory; immediate, where theby evolving in such a way that it is alwaysoperand is a part of the instruction. See also mathematically equivalent to the dark statecentral processing unit. that would be produced by coherent popu-c 2000 by CRC Press LLC 40. lation trapping. Adiabatic passage is oftenple, for a network described by the nodal ad-used for selective transfer of population be-mittance matrix, its adjoint network is repre-tween two long-lived states of a multistatesented by the transposed admittance matrixsystem, especially in cases where the two- of the original network. The adjoint networkstep process of absorption followed by spon- is a basic tool in the computer-aided sensi-taneous decay (optical pumping) would tend tivity analysis of electronic and microwaveto populate many other states. circuits.adjacency graph a graph in which eachadjustable-speed drive See variablenode represents an object, component, or fea-speed DC drive, variable speed AC drive.ture in an image. An edge between two nodesindicates two components that are touching admissible matrix a matrix M that canor connected in the image. be obtained by xing the free parameters of the matrix M at some particular values. M adjacent channel interference (ACI) theis said to be admissible with respect to M.interference caused by an adjacent frequencyband, e.g., in a system with frequency divi- admittance the reciprocal of thesion duplex (FDD). Classied as either in- impedance of an electric circuit.band or out-of-band adjacent channel inter-ference (ACI). The in-band ACI occurs when admittance inverter an idealized de-the center frequency of interfering signal falls vice or set of matrix parameters that func-within the band of the desired signal. The tions electrically like a quarter-wave losslessout-of-band ACI occurs when the center fre-transmission line of characteristic impedancequency of interfering signal falls outside the J at each frequency, thus transforming thebandwidth of the desired signal. load admittance (YLOAD ) by +90 degrees and modifying the magnitude, resulting in an in-adjacent channel leakage powerSeeput admittance (Yin ).adjacent channel power.J2Yin =Yloadadjacent channel power (ACP) a powerof distortion components generated in adja-admittance matrixthe inverse of thecent channel, which is caused by a nonlinear-impedance matrix in the method of moments.ity of high-power amplier amplifying a dig-itally modulated signal such as QPSK, QAM, ADPSee ammonium dihydrogen phosphate.etc. Adjacent channel power is dened as aratio of signal power in channel and leakagepower in adjacent channel. ADPCMSee adaptive differential pulse code modulation.adjacent channel reuse ratio (ACRR)the reuse ratio between radio communicationADSL See asymmetric digital subscribercells using adjacent radio channels. See alsoline.reuse ratio. adsorbentthe material of an adsorber,adjacent channels radio channels occu- for example, silica gel, alumina, and char-pying radio frequency allocations n and n1. coal. Adsorbent materials are characterized by high surface to volume ratio.adjoint network a network with an iden-tical structure to the original one, but withadsorber (1) condensation of a gas on thepossibly different elements. As an exam- solid material.c 2000 by CRC Press LLC 41. (2) material that attracts and holds (by Van Advanced Television Research Consor-der Waal forces) molecular layers of densetiuman organization consisting of Davidgases (i.e., very near condensation temper- Sarnoff Research Center, Thompson Con-atures) on porous high surface/volume ratio sumer Electronics, North American Philipsmaterials.Corporation, NBC, and Compression Labo-ratories.ADTVSee advanced digital television.aeolian vibrationa high-frequency me-chanical vibration of electric power linesadvanced compatible television (ACTV)caused by wind. an extended denition television system thatcan operate with existing bandwidths on ex- aerial cable any fully-insulated electricisting receivers and is compatible with the power cable which is carried overhead uponNTSC broadcasting system. The ACTV sys- poles, as opposed to the use of the more usualtem was proposed by the Advanced Televi-overhead bare conductors.sion Research Consortium and was the rsthigh denition television (HDTV) system.aerodynamic headSee disk head.HDTV system was tested by the FCC July17, 1992. The additional picture informationAFC See automatic frequency control.needed to increase the picture width and toincrease the resolution to the HDTV formatafne transforma geometric imageis transmitted in an augmented channel as transformation including one or more transla-an alternative to simulcast transmission. See tions, rotations, scales, and shears that is rep-Advanced Television Research Consortium.resented by a 4 4 matrix allowing multiplegeometric transformations in one transformadvanced digital television (ADTV)step. Afne transformations are purely lin-a high denition television (HDTV) digitalear and do not include perspective or warpingtransmission television system was proposed transformations.to the Federal Communications Commissionby the Advanced Television Research Con-AFMSee atomic force microscope.sortium. The ADTV system introduced alayered system to separately describe the dig-AFT See automatic ne tuning.ital transmission system, the video compres-sion system, and the data packet transportAFV See audio follow-video switcher.system. The video compression method usesAGCSee automatic gain control ora MPEG++ standard that provides for com-automatic generation control.patibility with multimedia computing. SeeAdvanced Television Research Consortium.agenta computational entity that actson behalf of other entities in an autonomousadvanced mobile phone system (AMPS) fashion.a standard for a cellular radio communi-cations network originally developed in the agent-based systeman application1970s by AT&T and later adopted as an in- whose component are agents. See alsodustry standard by the U.S.-based Telecom-agent.munications Industries Association (TIA). Itis the rst cellular standard widely deployed aggregationan operation performed onin North America. It is also referred to as the system variables whose purpose is to collectanalog cellular system. Frequency modula- them in a way enabling order and/or uncer-tion with 30 kHz channels is used.tainty reduction. For linear systems bothc 2000 by CRC Press LLC 42. continuous-time and discrete-time state ag-cross over another strip. Air bridges are alsogregation is obtained by linear transforma-used to suspend metalization in spiral induc-tion of the original state represented by an tors off of the semi-conducting substrate in aaggregation matrix G endowed with the fol- way that can lead to improved performancelowing properties: in some cases.GA = A G; GB = B ; CG = C ; air capacitora xed or variable capacitor in which air is the dielectric material betweenwhere A, B, C are original system matrices the capacitors plates.(respectively state, input, and output ones)and A , B , C are aggregated system ma- air circuit breaker a power circuittrices. The aggregation is an eigenvalues- breaker where the power co