Oscillator Phase Noise Reduction Using Nonlinear D

1、OscillatorPhaseNoiseReductionUsingNonlinearDesignTechniquesbyDavidS.M.SteinbachThesissubmittedtotheFacultyoftheVirginiaPolytechnicInstituteandStateUniversityinpartialfulfillmentoftherequirementsforthedegreeofMASTEROFSCIENCEinElectricalEngineeringDr.W.A.Davis,ChairmanDr.C.W.BostianDr.D.G.Sweeney8May2001Blacksburg,VirginiaKeyWords:Design,Nonlinear,Oscillator,Phasenoise,Copyright2001,DavidS.M.SteinbachOscillatorPhaseNoiseReductionUsingNonlinearDesignTechniquesDavidS.M.Steinbach(ABSTRACT)Phasenoise。

2、fromradiofrequency(RF)oscillatorsisoneofthemajorlimitingfactorsaffectingcommunicationsystemperformance.Phasenoisedirectlyeffectsshort-termfrequencystability,Bit-Error-Rate(BER),andphase-lockedloopadjacent-channelinterference.RFoscillatorcircuitscontainatleastoneactivedevice,usuallyatransistor.Theactivedevicehasnoisepropertieswhichgenerallydominatethenoisecharacteristiclimitsofanoscillator.Sinceallnoisesources,exceptthermalnoise,aregenerallyproportionaltoaveragecurrentflowthroughtheactivedevice,i。

3、tislogicalthatreducingthecurrentflowthroughthedevicewillleadtolowernoiselevels.Atheorybasedonthetime-varyingpropertiesofoscillatorsproposesthatnarrowingthecurrentpulsewidthintheactivedevicewilldecreasethetimethatnoiseispresentinthecircuitandtherefore,decreasephasenoiseevenfurther.Thetime-domainwaveformsandphasenoiseofanactive-biased700MHzoscillatorareanalyzed,showingheavysaturationandhigh-harmoniccontent.Redesignsoftheexampleoscillatorinactive-biasandfour-resistor-biasconfigurationsshowimprovedp。

4、hasenoiseandlowerharmoniclevelsattheoutput.Fiveoscillatordesignsofeachbiasconfiguration,eachhavingadifferentpulsewidth,aresimulated.Aspredictedbythetheory,thenarrowestcurrentpulsecorrespondstothelowestphasenoiseofthesimulatedoscillators.iiiAcknowledgmentsIwishtothankmyadvisor,Dr.WilliamA.Davis,forofferingmemuchneededdirectionandagreatdealofknowledgeandexperiencefromwhichtodraw.Mycommitteemembers,Dr.CharlesW.BostianandDr.DennisG.Sweeney,alsodeservethanksfortheirmuchappreciatedencouragementandinsi。

5、ghtintoproblemsencounteredoverthispastyear.IamverygratefulforencouragementprovidedbymyfamilyandfriendSharonSmith.HadIbeenwithoutsuchsupport,mygraduatestudiescouldnothavebeenpossible.ThisworkwasfundedbyBAEthroughtheVirginiaTechCenterforWirelessTelecommunication(CWT)affiliateprogram.BAEisaleadingmanufacturerofcustomanaloganddigitalradiocommunicationshardware.ivTableofContentsChapter1.Introduction..........................................................................................11.1Literatur。

6、eReview..........................................................................................2Chapter2.Background...........................................................................................42.1OscillatorFundamentals.................................................................................42.2Design...........................................................................................................52.2.1NonlinearSources..............................................。

7、.............................52.2.2ThreeTerminalModel....................................................................72.2.3OscillatorDesign............................................................................92.3Noise...........................................................................................................15...........................................................................162.3.1SourcesofNoise................................................................182。

8、.3.2OscillatorNoiseModelsChapter3.Verification.........................................................................................233.1HowADSSimulatesNoise..........................................................................243.2BasicOscillatorSimulations.........................................................................253.2.1700MHzExample..........................................................................253.2.2RedesignwithActiveBias.......................................。

9、......................273.2.3RedesignwithFour-ResistorBias.................................................30..........................................................323.2.4RedesignNoiseComparison3.3PhaseNoise-PulseWidthComparison........................................................32Chapter4.ConclusionsandRecommendationsforFutureWork......................38References...............................................................................................................40Vita.........。

10、................................................................................................................41vListofFiguresFigure2.1.Feedbackoscillatormodel.........................................................................4Figure2.2.ExponentialcharacteristicofBJT..............................................................6Figure2.3.FouriercoefficientsforBJTcharacteristic.................................................8Figure2.4.Common-base,common-collector,andcommon-emitterColpitts。