相位噪声&抖动仿真方法VCO-Design-Using-SpectreRF

________________________________________________________________________June2006ProductVersion6.1SpectreRFWorkshopVCODesignUsingSpectreRFMMSIM61June2006VCODesignUsingSpectreRF________________________________________________________________________June2006ProductVersion6.12ContentsVoltageControlledOscillatorDesignMeasurements........................................................3Purpose............................................................................................................................3Audience.........................................................................................................................3Overview.........................................................................................................................3IntroductiontoVCOs..........................................................................................................3TheDesignExample:oscHartley.......................................................................................4ExampleMeasurementsUsingSpectreRF..........................................................................5Lab1:OutputFrequency,OutputPower,PhaseNoiseandJitter...................................6Measurement(PnoisewithshootingorFlexibleBalanceengine)..................................6Lab2:FrequencyPushing(SweptPSS)........................................................................31Lab3:TuningSensitivityandLinearity(SweptPSS)...................................................36Lab4:PowerDissipation(PSS)...................................................................................43Lab5:FrequencyPulling(SweptPSS)........................................................................48Conclusion........................................................................................................................62Reference..........................................................................................................................62VCODesignUsingSpectreRF________________________________________________________________________June2006ProductVersion6.13VCODesignUsingSpectreRFTheproceduresdescribedinthisworkshoparedeliberatelybroadandgeneric.Yourspecificdesignmightrequireproceduresthatareslightlydifferentfromtheonesdescribedinthisapplicationnote.PurposeThisworkshoppresentshowtouseSpectreRFintheAnalogDesignEnvironmenttomeasureparameterswhichareimportantindesignverificationofvoltagecontrolledoscillators,orVCO.NewfeaturesofMMSIM6.0USR2areincluded.AudienceUsersofSpectreRFintheAnalogDesignEnvironment.OverviewThisapplicationnoteprovidestheuserwithabasicsetofcommonmeasurementsforVCO.IntroductiontoVCOsOscillatorsgenerateareferencesignalataparticularfrequency.Involtagecontrolledoscillators,orVCOs,thefrequencyoftheoutputvariesinproportiontosomecontrolsignal.OscillatorsaregenerallyusedinRFcircuitstogeneratethelocaloscillator,orLO,signalformixers.VCOsareusedinbothreceiversandtransmitters.ThenoiseperformanceofamixerisstronglyaffectedbynoiseontheLOsignal.TheLOsignalisalwayspassedthroughalimiter,whichisgenerallybuiltintothemixer,tomakethemixerlesssensitivetosmallvariationsintheamplitudeoftheLOsignal.Oscillators,exceptforreferenceoscillators,areembeddedinphase-lockedloopstocontrolPLLsfrequencyandreducetheirphasenoise.Referenceoscillatorsaregenerallyfixed-frequencycrystaloscillators,andassuchhavewellcontrolledfrequencyandnoise.However,oscillatorsstillproduceenoughvariationinthephaseoftheiroutputtoaffecttheperformanceofthetransceiver.Thus,itisimportanttominimizethephasenoiseproducedbytheoscillator.VCODesignUsingSpectreRF________________________________________________________________________June2006ProductVersion6.14TheDesignExample:oscHartleyTheVCOmeasurementsdescribedinthisworkshoparecalculatedusingSpectreRFintheAnalogDesignEnvironment.ThedesigninvestigatedistheHartleyoscillatorshownbelow:TheoscHartleyVCOusesthebasicHartleytopologyandistunablebetween720MHzand1.1GHz.Theoscillationfrequency(Fo)isdeterminedbytheresonantcircuitmadeupofinductors(L0,L1)andtheC1capacitor.InthisparticularVCO,thevaluesofL1andL2arefixedwhereasthevalueofC1isvariable.Inthisexample,theresonantcircuit'scapacitorC1servesasavaractordiode.Asaresult,thevaractordiode'sjunctioncapacitance,varC,isafunctionoftheappliedvoltageasshowninthefollowingequation.VCODesignUsingSpectreRF________________________________________________________________________June2006ProductVersion6.15γφ+=VCCj10varWhere■V=appliedjunctionvoltage(V)■0jC=junctioncapacitance(F)forV=0V■f=barrierpotential(V)■γ=junctiongradientcoefficientThevaractordiodeforthisVCOhasthefollowingvalues■0jC=8pF■f=0.75V■γ=0.4BecausevarCisinverselyproportionaltoV,andFoisinverselyproportionaltovarC,theoscillationfrequencyisproportionaltoV.Inotherwords,asyouincreaseV,varCdecreasesandFoincreases.ExampleMeasurementsUsingSpectreRFToachieveoptimalcircuitperformance,youshouldmeasureandevaluateseveralVCOcharacteristicsorparametersundervaryingconditions.Asanexample,onefundamentalmeasurement