信號發(fā)生器的基本知識

AgendaTypesofsourcesCWSweptSignalGeneratorBlockDiagramsApplicationsSpecifications1SourceBasicsSourcesGenerateSineWavesVoltageTimeVoltageFrequencyThisistheidealoutput:mostspecsdealwithdeviationsfromtheidealandaddingmodulationtoasinewaveRFMicrowaveMillimeter20-50GHz300GHz3-6GHzSpectrumAnalyzerOscilloscope2SourceBasicsTypesofSourcesCWgeneratesasinglefrequency,fixedsinewaveSweptsweepsoverarangeoffrequenciesmaybephasecontinuousSignalGeneratoraddsmodulationproduces“realworld”signal3SourceBasicsAgendaTypesofsourcesCWSweptSignalGeneratorBlockDiagramsApplicationsSpecifications4SourceBasicsCWSourceSpecifications...FrequencyVoltageFrequencyUncertaintyRange:RangeoffrequenciescoveredbythesourceResolution:Smallestfrequencyincrement.Accuracy:Howaccuratelycanthesourcefrequencybeset.EXAMPLEAccuracy=

= CWfrequency=1GHz

= agingrate=0.152ppm/year = timesincelastcalibrated=1year

+_fCWtagingcalt**fCWtagingcaltAccuracy=152Hz+_5SourceBasicsCWSourceSpecifications...AmplitudeDUTSourceprotectedfromaccidentaltransmissionfromDUTVoltageFrequencyHowaccurateisthisnumber?WhatisPout?WhatisPout?maxminRange(-136dBmto+13dBm)Accuracy(+/-0.5dB)Resolution(0.02dB)SwitchingSpeed(25ms)ReversePowerProtection6SourceBasicsPhaseNoiseResidualFMSpuriousCWSourceSpecifications...SpectralPuritynon-harmonicspur~65dBcharmonicspur~30dBcCWoutputResidualFMistheintegratedphasenoiseover300Hz-3kHzBWphasenoise

0.5f0f0

2f0sub-harmonics7SourceBasicsCWSourceSpecifications...SpectralPurity:PhaseNoiseCWoutputfrequencyPowerSpectralDensitymeasuredasdBc/HzCh1PMPSD1k10k100kTRACEA:AMarker10000Hz75dBc/Hz-125dBc/HzLogMag5dBc/div-105dBc/Hz8SourceBasicsRFCWBlockDiagramReferenceOscillatorfVCOPhaseDetectorFrac-NdividebyXALCModulatorALCDriverALCDetectorOutputAttenuatorALC=automaticlevelcontrolReferenceSectionSynthesizerSectionOutputSection9SourceBasicsRFCWBlockDiagramReferenceSectionfPhaseDetectorOptionalExternalReferenceInputReferenceOscillator(TCXOorOCXO)

TCXOOCXOAgingRate+/-2ppm/year+/-0.1ppm/yearTemp.+/-1ppm+/-0.01ppmLineVoltage+/-0.5ppm+/-0.001ppmtosynthesizersectiondividebyX10SourceBasicsRFCWBlockDiagramSynthesizerSectionfVCOPhaseDetectorFrac-NfromreferencesectiontooutputsectionX2multiplierFrontpanelcontrol5MHz465.5MHzN=93.1931MHz5MHducesaccurate,cleansignals11SourceBasicsRFCWBlockDiagramSynthesizerSectionreferenceoscillatorphasenoiseofsourceVCOnoisephasedetectornoisebroadbandnoisefloor20logNphase-locked-loop(PLL)bandwidthselectedforoptimumnoiseperformancePLL/Fractional-N...suppressesphasenoisefrequencynoise12SourceBasicsRFCWBlockDiagramOutputSectionALC=automaticlevelcontrolALCModulatorALCDriverALCDetectorOutputAttenuatorfromsynthesizersectionsourceoutputALCmaintainsoutputpowerbyadding/subtractingpowerasneededOutputAttenuatormechanicalorelectronicprovidesattentuationtoachievewideoutputrange(e.g.-136dBmto+13dBm)13SourceBasicsmWaveCWBlockDiagramALCDetectorALCModulatorALCDriverOutputAttenuatorSamplerReferenceSectionSynthesizerSectionOutputSectionRefOscfVCOPhaseDetFracNbyXfVCOPhaseDetectorFrac-NfPhaseDetectorTuningCoilsYIGOscillator14SourceBasicsApplications&CriticalSpecificationsLocalOscillatorphasenoisefrequencyaccuracyAmplifierDistortionspuriousTOI(forsystem)ReceiverTestingSpuriousspuriouslevelaccuracy15SourceBasicsApplications&CriticalSpecificationsAsaLocalOscillatorIFsignaltransmitteroutputpoorphasenoisespreadsenergyintoadjacentchannelspoorfrequencyaccuracywillcausetransmittertobeatthewrongfrequencyDUT16SourceBasicsApplications&CriticalSpecificationsAmplifierTestingf2f1fU=2f2-f1fL=2f1-f2spurioussignalsfromsourcecancorruptmeasurementfrequencyamplitudetestsystemthirdorderproductswillalsofallhereoutputRFisolatorf1f2DUTIntermodulationDistortion17SourceBasicsApplications&CriticalSpecificationsReceiverTestingIFRejectionCurveFrequencyLevel(dBm)spurfromsourceand/orhighlevelsofphasenoisecancauseagoodreceivertofailsourceoutputIFsignalin-channelsignal(modulatedsignal)out-of-channelsignal(CWormodulatedsignal)DUTReceiverSelectivity18SourceBasicsAgilentFamiliesofCWGeneratorsRFMicrowaveAgilent8664/65family100MHz-6GHzLowoutchannelnoiseAM/FM/Pulse.Agilent8662/63family100KHz-2.5GHzLowinchannelnoiseAM/FM/Phase/PulseAgilent83711/12Bfamily10MHz-20GHzCWonly19SourceBasicsAgendaTypesofsourcesCWSweptSignalGeneratorBlockDiagramsApplicationsSpecifications20SourceBasicsSweeperSpecifications...Frequencyrampsweepaccuracysweeptimeresolutionstepsweepaccuracynumberofpointsswitchingtimetimefrequencyf2t2t1f1t4t3t1t2f4f3f1f2frequency21SourceBasicsSweeperSpecifications...AmplitudeFrequencySweepLevelAccuracyFlatnessSourceMatch(SWR)

PowerSweepPowerSweepRangePowerSlopeRangeSourceMatch(SWR)flatnessspeclevelaccuracyspecf1f2frequencypowerpower}P2P1powersweepranget1t222SourceBasicsApplications&CriticalSpecificationsFrequencyResponseFrequencyAccuracyOutputPower(Level)AccuracyFlatnessSpeedresidualFMAmplifierCompressionPowerRange23SourceBasicsApplications&CriticalSpecificationsFrequencyResponseTestingLOSweeperInputFrequencyAccuracyOutputPower(Level)AccuracyFlatnessSpeedresidualFM24SourceBasicsApplications&CriticalSpecificationsFrequencyResponseTestingCenter2450.212MHzSpan1099.577MHz11356BW:429.600MHzCF:2405.782MHzQ:5.60Loss:-0.84dB1:TransmissionLogMag5.0dB/Ref-15.00dB-35-30-25-20-10-505AbsdBCh1WhoCaresAboutAccuracy?25SourceBasicsApplications&CriticalSpecificationsAmplifierCompressionPowerInPowerOut1dBcompressionpointThe1dBcompressionpointisacommonamplifierspecificationusedtoidentifythelinearoperatingrangeofanamplifier.PowersweepisavailableonsomeAgilentsources.PowerRange26SourceBasicsSynthesizedSweepGeneratorsAgilent83750SeriesStep/AnalogsweepAM/FM/Phasemodulation10MHzto20GHzupto110GHzwith83550seriesmodulesandamplifier

Agilent8360LSeriesStep/Analogsweep8510/8757Compatibility10MHzto50GHzupto110GHzwith83550seriesmodules27SourceBasicsAgendaTypesofsourcesCWSweptSignalGeneratorBlockDiagramsApplicationsSpecifications28SourceBasicsSignalGeneratorsCalibratedmodulationAnalog(AM,FM,PM,Pulse)Digital(I-Q)FormatSpecific(TDMA,CDMA,etc.)29SourceBasicsModulation...WheretheinformationresidesAM,PulseFMPMqV=A(t)sin[(t)]pV=A(t)sin[2f(t)+(t)]f30SourceBasicsModulation:AnalogAmplitudeModulationImportantSignalGeneratorSpecsforAmplitudeModulationVoltageTimeCarrierModulationModulationfrequencyLinearAMLogAMDepthofmodulation(ModIndex)31SourceBasicsModulation:AnalogFrequencyModulationVoltageTimeImportantSignalGeneratorSpecsforFrequencyModulationV=Asin[2ft+m(t)]pcbF/Fdevmodb=DFrequencyDeviationModulationFrequencydcFMAccuracyResolution32SourceBasicsModulation:AnalogPhaseModulationb=Df

peakV=Asin[2pft+m(t)]ImportantSignalGeneratorSpecsforPhaseModulationPhasedeviationRatesAccuracyResolutionVoltageTimecb33SourceBasicsModulation:AnalogPulseModulationTimePulseOn/OffratioRisetimeRate=1/TTWidthPowert1/t1/TPowerImportantSignalGeneratorSpecsforPulseModulationPulsewidthPulseperiodOn/OffratioRisetime34SourceBasicsDigitalModulation...signalcharacteristicstomodifyAmplitudeFrequencyPhaseBothAmplitudeandPhase35SourceBasicsDigitalModulationPolarDisplay:Magnitude&PhaseRepresentedTogetherMagnitudeisanabsolutevaluePhaseisrelativetoareferencesignalPhaseMag0deg36SourceBasicsDigitalModulationSignalChangesorModificationsPhaseMag0degMagnitudeChangePhase0degPhaseChangeFrequencyChangeBothChange0deg0deg37SourceBasicsDigitalModulation...BinaryPhaseShiftKeying(BPSK)fV=Asin[2ft+(t)](t) =f1f2pf38SourceBasicsDigitalModulationBPSKIQDiagramIQ01OneBitPerSymbolSymbolRate=BitRate39SourceBasicsDigitalModulation...QuadraturePhaseShiftKeying(QPSK)V=Asin[2ft+(t)]f(t) =f1=3/4pf2=/4pf3=-/4pf4=-3/4ppf40SourceBasicsDigitalModulationQPSKIQDiagramIQ0001101141SourceBasicsDigitalModulationp/4DQPSKIQDiagramIQ42SourceBasicsDigitalModulationModulationAccuracy{IQMagnitudeError(IQerrormag)ErrorVectorIdeal(Reference)SignalPhaseError(IQerrorphase)TestSignalf43SourceBasicsDigitalSignalGeneratorBlockDiagramIQModulatormodulationqualityBasebandGeneratormodulationqualityadjacentchannelperformancesupportedmodulationformatsreferencesection(suppliestiming)tooutputsection44SourceBasicsDigitalModulationPSKImplementation:IQMethodp/2CarrierGoodInterfacewithDigitalSignalsandCircuitsCanbeImplementedwithSimpleCircuitsCanbeModifiedforBandwidthEfficiencyI:Q:45SourceBasicsDigitalSignalGeneratorBlockDiagramIQModulatorp/2DACDACExtIExtQfromsynthesizersectiontooutputsectionQfromBasebandGeneratorIfromBasebandGenerator46SourceBasicsDigitalSignalGeneratorBlockDiagramBasebandGeneratorDACDACPatternRAMConstellationMapandBasebandFiltersTimingDataDataClockSymbolClockFromCPUIQAnalogReconstructionFilters47SourceBasicsDigitalSignalGeneratorFormatSpecificDigitalSignalsNADC(TDMAIS-54)

ParameterSpecificationAccessMethodTDMA/FDDModulationp/4DQPSKChannelBandwidth30kHzReverseChannelFrequencyBand824-849MHzForwardChannelFrequencyBand869-894MHzFiltering0.35RRC48SourceBasicsDigitalSignalGeneratorAccessandFramingoneframe=1944bits(972symbols)=40ms;25frames/secslot1slot2slot3slot4slot5slot6324bit(162symbols)=6.667msGRDataSyncDataSACCHCDVCCData6616281221212122MobiletoBaseStation49SourceBasicsApplicationsandCriticalSpecificationsAnalogandDigitalReceiverSensitivityfrequencyaccuracylevelaccuracyerrorvectormagnitudeReceiverSelectivityphasenoisespuriousspectralaccuracySpectralRegrowthACPperformance50SourceBasicsApplicationsandCriticalSpecificationsReceiverSensitivity

WanttomeasuresensitivityinachannelMeasurementimpairedbyfrequencyinaccuracyfrequencyinaccuracyamplitudeinaccuracyinputforsignalgeneratorDUTFrequencyAccuracy51SourceBasicsApplicationsandCriticalSpecificationsReceiverSensitivity

Customeristestinga-110dBsensitivitypager:PowerOut-110dBspecificationCase1:Sourcehas+/-5dBofoutputpoweraccuracyat-100to-120dBmoutputpower.Setsourceto-115dBmActualoutputpower=-114dBmXXXXXOCase2:Sourcehas+/-1dBofoutputpoweraccuracyat-100to-120dBmoutputpower.PowerOut-110dBspecificationSetsourceto-111dBmActualoutput