COMPREHENSIVE DICTIONARY OF ELECTRICAL ENGINEERING EDITOR-IN-CHIEF Phillip A Laplante Boca Raton London New York CRC Press is an imprint of the Taylor & Francis Group, an informa business CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 © 1998 by Taylor & Francis Group, LLC CRC Press is an imprint of Taylor & Francis Group, an Informa business No claim to original U.S. Government works Version Date: 20150212 International Standard Book Number-13: 978-1-4398-7498-1 (eBook - PDF) This book contains information obtained from authentic and highly regarded sources. Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the valid- ity of all materials or the consequences of their use. The authors and publishers have attempted to trace the copyright holders of all material reproduced in this publication and apologize to copyright holders if permission to publish in this form has not been obtained. If any copyright material has not been acknowledged please write and let us know so we may rectify in any future reprint. Except as permitted under U.S. Copyright Law, no part of this book may be reprinted, reproduced, transmitted, or uti- lized in any form by any electronic, mechanical, or other means, now known or hereafter invented, including photocopy- ing, microfilming, and recording, or in any information storage or retrieval system, without written permission from the publishers. For permission to photocopy or use material electronically from this work, please access www.copyright.com (http:// www.copyright.com/) or contact the Copyright Clearance Center, Inc. (CCC), 222 Rosewood Drive, Danvers, MA 01923, 978-750-8400. CCC is a not-for-profit organization that provides licenses and registration for a variety of users. For organizations that have been granted a photocopy license by the CCC, a separate system of payment has been arranged. Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation without intent to infringe. Visit the Taylor & Francis Web site at http://www.taylorandfrancis.com and the CRC Press Web site at http://www.crcpress.com Preface One can only appreciate the magnitude of effort 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 then an exercise in writing. And although I have managed organizations of up to 80 academics, nothing is more like“herdingcats”thanmotivatinganinternationalcollectionofmorethan100distin- guishedengineers,scientists,andeducatorsscatteredaroundtheglobealmostentirely 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 benefits 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-Chief President Pennsylvania Institute of Technology Media, Pennsylvania Editorial Board MikeFiddy LaurenLaplante UniversityofMassachusetts,Lowell PublicServiceElectricandGas Editor:Electro-opticalandlightwavesystems Editor:Propertiesofmaterials MikeGolio SudhakarMuddu RockwellCollins SiliconGraphics Editor:Microwavesystems Co-Editor:Digitalelectronics,VLSI,hardware descriptionlanguage LingGuan MeredithNole UniversityofSydney AmericanEfficientLighting Editor:Communicationsandinformation Editor:Illumination processing MarcoGori AmosOmondi UniversityofFlorence FlindersUniversity AssociateEditor:InformationProcessing Editor:Computerengineering(I/Oandstorage) BobHerrick IanOppermann PurdueUniversity UniversityofSydney Editor:RF,radioandtelevision AssociateEditor:Communication JeffHonchell JohnPrince PurdueUniversity UniversityofArizona AssociateEditor:RF,radioandtelevision Editor:Packaging JinJiang MarkReed UniversityofWesternOntario YaleUniversity Editor:Circuitsandsystems Editor:Microelectronicsandsolidstatedevices TadeuszKaczorek DavidShively WarsawUniversityofTechnology ShivelyEngineering Editor:Controlsystems Editor:Electromagnetics AndrewKang TimSkvarenina UniversityofCaliforniaatBerkeley PurdueUniversity Co-Editor:Digitalelectronics,VLSI,hardware Editor:Electricmachinesandpowerelectronics descriptionlanguage MarkKinsler Editor:Powersystems EugeneVeklerov JanuszZalewski LawrenceBerkeleyLabs UniversityofCentralFlorida Editor:Signalandimageprocessing Editor:Computerengineering(processors) Foreword How was the dictionary constructed? As I knew this project would require a divide-and-conquer approach with fault- tolerance,Isoughttopartitionthedictionarybydefiningareasthatcoveredallaspects of Electrical Engineering. I then matched these up to IEEE defined interest areas to ensure that complete coverage was provided. This created a great deal of overlap, which was intentional. I knew that terms needed to be defined several different ways, depending on usage and I needed to ensure that every term would be defined at least once. The mapping of the Dictionary’s areas to the IEEE interest areas are as follows: Powersystems Circuitsandsystems •PowerEngineering •CircuitsandSystems •PowerElectronics •InstrumentsandMeasurements Electricmotorsandmachines Controlsystems •PowerEngineering •ControlSystems •PowerElectronics •RoboticsandAutomation Digitalelectronics,VLSI,hardware Electromagnetics descriptionlanguage •ElectromagneticCompatibility •ConsumerElectronics •Magnetics •ElectronicDevices •IndustrialElectronics •InstrumentsandMeasurements Computerengineering(processors) •Computer Microelectronicsandsolidstatedevices •IndustrialElectronics Computerengineering(I/Oandstorage) •InstrumentsandMeasurements •Computer RF,radio,andtelevision Microwavesystems •BroadcastTechnology •AntennasandPropagation •MicrowaveTheoryandTechniques Communicationsandinformationprocessing •Communications Electro-opticalandlightwavesystems •InformationTheory •LasersandElectro-Optics •Systems,Man,andCybernetics •Reliability Illumination Signalandimageprocessing Propertiesofmaterials •SignalProcessing •DielectricsandElectricalInsulation •Systems,Man,andCybernetics Packaging •Components,Packaging,and •ManufacturingTechnology Note that Software Engineering was not included as an area, and most software terms have been omitted. Those that were included were done so because they relate to some aspect of assembly language programming or low-level control, or artificial intelligence and robotics. For those interested in software engineering terms, CRC’s forthcoming Comprehensive Dictionary of Computer Science, Engineering and Tech- nology will include those terms. SeveralotherIEEEinterestareaswerenotexplicitlyassignedtoareaeditors. How- ever, after discussing this fact with the Editorial Board, it was decided that relevant terms of a general nature would be picked up and terms that were not tagged for the dictionary from these areas were probably too esoteric to be included. These interest areas are: AerospaceandElectronicSystems GeosienceandRemoteSensing Education IndustryApplications EngineeringinMedicineandBiology NuclearandPlasmaScience EngineeringManagement OceanicEngineering ProfessionalCommunications Ultrasonic,Ferroelectrics,andFrequencyControl SocialImplicationsofTechnology VehicularTechnology Given the Area Editor structure, constructing the dictionary then consisted of the following steps: 1. Creating a terms list for each area 2. Defining terms 3. Cross-checking terms within areas 4. Cross-checking terms across areas 5. Compiling and proofing the terms and definitions 6. Reviewing compiled dictionary 7. Final proofreading The first and most important task undertaken by the area editors was to develop a list of terms to be defined. A terms list is a list of terms (without definitions), proper names (such as important historical figures or companies), or acronyms relating to ElectricalEngineering. Whatwentintoeachtermslistwaslefttothedesecrationofthe area editor based on the recommendations of the contributing authors. However, lists were to include all technical terms that relate to the area (and subareas). Technical terms of a historical nature were only included if it was noted in the definition that the term is “not used” in modern engineering or that the term is “historical” only. Althoughthenumberoftermsineachlistvariedsomewhat,eacharea’stermslistwill consisted of approximately 700 items. Oncethetermslistswerecreated,theyweremergedandscrutinizedforanyobvious omissions. These missing terms were then assigned to the appropriate area editor. At this point the area editors and their contributing authors (there were 2 to 10 contributing authors per area) began the painstaking task of term definition. This process took many months. Once all of the terms and their definitions were collected, the process of converting, merging, and editing began. Thedictionaryincludedcontributionsfromover100contributorsfrom10countries. Although authors were provided with a set of guidelines to write terms definitions, they were free to exercise their own judgment and to use their own style. As a result, the entries vary widely in content from short, one-sentence definitions to rather long dissertations. While I tried to provide some homogeneity in the process of editing, I neither wanted to tread on the feet of the experts and possibly corrupt the meaning of the definitions (after all, I am not an expert in any of the representative areas of the dictionary) nor did I want to interfere with the individual styles of the authors. As a result, I think the dictionary contains a diverse and rich exposition that collec- tively provides good insights into the areas intended to be covered by the dictionary. Moreover, I was pleased to find 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 The Control Handbook, Electronics Handbook, Image Processing Handbook, Circuits and Filters Handbook, and The Electrical Engineering Handbook, to pick up any defini- tions that were missing or incomplete. About 1000 terms were take from the CRC handbooks. We also borrowed, with permission from IEEE, about 40 definitions that could not be found elsewhere or could not be improved upon. Despite the incredible support from my area editors, individual contributors, and staffatCRCPress,thefinaltaskofarbitratingconflictingdefinitions,rewordingthose that did not seem descriptive enough, and identifying missing ones was left to me. I hope that I have not failed you terribly in my task. How to use the dictionary The dictionary is organized like a standard language dictionary except that not ev- ery word used in the dictionary is defined there (this would necessitate a complete embedding of an English dictionary). However, we tried to define most non-obvious technical terms used in the definition of another term. In some cases more than one definition is given for a term. These are denoted (1), (2), (3), ..., etc. Multiple definitions were given in cases where the term has multiple distinct meanings in differing fields, or when more than one equivalent but uniquely descriptive definition was available to help increase understanding. In a few cases, I justcouldn’tdecidebetweentwodefinitions. Pickthedefinitionthatseemstofityour situation most closely. The notation 1., 2., etc. is used to itemize certain elements of a definition and are not to be confused with multiple definitions. Acronymtermsarelistedbytheirexpandedname. Undertheacronymthereaderis referred to that term. For example, if you look up “RISC” you will find “See reduced instruction set computer,” where the definition can be found. The only exceptions are in the cases where the expanded acronym might not make sense, or where the acronym 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 the dictionary and I am sure that many have been omitted. Finally, we tried to avoid proprietary names and tradenames where possible. Some have crept in because of their importance, however. Acknowledgments A project of this scope literally requires hundreds of participants. I would like to take this 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,believinginme,andprovidingincrediblesupportandencouragement. • FrankMacCrory,NormaTrueblood,NoraKonopka,CaroleSweatman,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 PhysicseditorStanGibiliscoforsharingmanyideaswithme. • My friend Peter Gordon for many of the biographical entries. • Lisa Levine for providing excellent copy editing of the final manuscript. FinallytomywifeNancyandchildrenChristopherandCharlottefortheirincredible patience and endurance while I literally spent hundreds of hours to enable the birth of 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 and will be remedied in future printings of this dictionary. How to Report Errors/Omissions Because of the magnitude of this undertaking and because we attempted to develop new definitions completely from scratch, we have surely omitted (though not deliber- ately)manyterms. Inaddition,somedefinitionsarepossiblyincomplete,weak,oreven incorrect. But we wish to evolve and improve this dictionary in subsequent printings and editions. You are encouraged to participate in this collaborative, global process. Pleasesendanysuggestedcorrections,improvements,ornewtermstobeadded(along with suggested definitions) to me at [email protected] or [email protected]. If your submission is incorporated, you will be recognized as a contributor in future editions of the dictionary.