基于ad9854扫频信号源的设计翻译.docx
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基于ad9854扫频信号源的设计翻译
基于ad9854扫频信号源的设计-翻译
苏州大学本科生毕业设计(论文)附件:
外文文献资料与中文翻译稿
外文文献资料
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苏州大学应用技术学院10电子,学号1016405013,黄海浩
IntroductiontoAD9854
GENERALDESCRIPTION
TheAD9854ispin-for-pincomTheAD9854digitalsynthesizerisahighlyintegrateddevicethatusesadvancedDDStechnology,coupledwithtwointernalhighspeed,highperformancequadratureDACstoformadigitallyprogrammableIandQsynthesizerfunction.Whenreferencedtoanaccurateclocksource,theAD9854generateshighlystable,frequency-phase,amplitude-programmablesineandcosineoutputsthatcanbeusedasanagileLOincommunications,radar,andmanyotherapplications.TheinnovativehighspeedDDScoreoftheAD9854provides48-bitfrequencyresolution(1μHztuningresolutionwith300MHzSYSCLK).Maintaining17bitsensuresexcellentSFDR.
ThecircuitarchitectureoftheAD9854allowsthegenerationofsimultaneousquadratureoutputsignalsatfrequenciesupto150MHz,whichcanbedigitallytunedatarateofupto100millionnewfrequenciespersecond.Thesinewaveoutput(externallyfiltered)canbeconvertedtoasquarewavebytheinternal
foragileclockgeneratorapplications.Thedeviceprovidestwo14-bitcomparator
phaseregistersandasinglepinforBPSKoperation.
Forhigher-orderPSKoperation,theI/Ointerfacecanbeusedforphasechanges.The12-bitIandQDACs,coupledwiththeinnovativeDDSarchitecture,provideexcellentwidebandandnarrow-bandoutputSFDR.TheQDACcanalsobeconfiguredasauser-programmablecontrolDACifthequadraturefunctionisnotdesired.Whenconfiguredwiththecomparator,the12-bitcontrolDACfacilitatesstaticdutycyclecontrolinhighspeedclockgeneratorapplications.
Two12-bitdigitalmultiplierspermitprogrammableamplitudemodulation,on/offoutputshapedkeying,andpreciseamplitudecontrolofthequadratureoutput.Chirpfunctionalityisalsoincludedtofacilitatewidebandwidthfrequencysweepingapplications.Theprogrammable4×to20×REFCLKmultipliercircuitof
theAD9854internallygeneratesthe300MHzsystemclockfromanexternallower
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苏州大学本科生毕业设计(论文)附件:
外文文献资料与中文翻译稿
frequencyreferenceclock.Thissavestheusertheexpenseanddifficultyofimplementinga300MHzsystemclocksource.
Direct300MHzclockingisalsoaccommodatedwitheithersingle-endedordifferentialinputs.Single-pinconventionalFSKandtheenhancedspectralqualitiesoframpedFSKaresupported.TheAD9854usesadvanced0.35μmCMOS
technologytoprovideahighleveloffunctionalityonasingle3.3patiblewiththeAD9852single-tonesynthesizer.Itisspecifiedtooperateovertheextendedindustrialtemperaturerangeof?
40?
Cto+85?
C.
THEORYOFOPERATION
TheAD9854quadratureoutputdigitalsynthesizerisahighlyflexibledevicethataddressesawiderangeofapplications.ThedeviceconsistsofanNCOwitha48-bitphaseaccumulator,aprogrammablereferenceclockmultiplier,inversesincfilters,
digitalmultipliers,two12-bit/300MHzDACs,ahighspeedanalogcomparator,andinterfacelogic.ThishighlyintegrateddevicecanbeconfiguredtoserveasasynthesizedLO,anagileclockgenerator,oranFSK/BPSKmodulator.
AnalogDevices,Inc.,providesatechnicaltutorialabouttheoperationaltheoryofthefunctionalblocksofthedevice.ThetutorialincludesatechnicaldescriptionofthesignalflowthroughaDDSdeviceandprovidesbasicapplicationsinformationforavarietyofdigitalsynthesisimplementations.Thedocument,ATechnicalTutorialonDigitalSignalSynthesis,isavailablefromtheDDSTechnicalLibrary,ontheAnalogDevicesDDSwebsiteat
MODESOFOPERATION
TheAD9854hasfiveprogrammableoperationalmodes.Toselectamode,threebitsinthecontrolregister(parallelAddress1Fhex)mustbeprogrammed,asdescribedinTable5.
Table5.ModeSelectionTable
Mode2Mode1Mode0Result
000Singletone
001FSK
010RampedFSK
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苏州大学本科生毕业设计(论文)附件:
外文文献资料与中文翻译稿
011Chirp
100BPSK
INTERNALANDEXTERNALUPDATECLOCK
ThisupdateclockfunctioniscomprisedofabidirectionalI/Opin(Pin20)andaprogrammable32-bitdown-counter.ToprogramchangesthataretobetransferredfromtheI/ObufferregisterstotheactivecoreoftheDDS,aclocksignal(low-to-highedge)mustbeexternallysuppliedtoPin20orinternallygeneratedbythe32-bitupdateclock.
Whentheuserprovidesanexternalupdateclock,itisinternallysynchronizedwiththesystemclocktopreventapartialtransferofprogramregisterinformationduetoaviolationofdatasetuporholdtime.Thismodeallowstheusertocompletelycontrolwhenupdatedprograminformationbecomeseffective.Thedefaultmodefortheupdateclockisinternal(theinternalupdateclockcontrolregisterbitislogichigh).Toswitchtoexternalupdateclockmode,theinternalupdateclockcontrolregiste