高速数字混合锁相环频率合成器大学毕业论文外文文献翻译及原文.docx
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高速数字混合锁相环频率合成器大学毕业论文外文文献翻译及原文.docx
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高速数字混合锁相环频率合成器大学毕业论文外文文献翻译及原文
毕业设计(论文)
外文文献翻译
文献、资料中文题目:
高速数字混合锁相环频率合成器
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通信工程
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翻译日期:
2017.02.14
锁相技术译文翻译
英文原名:
HighSpeedDigitalHybridPLLFrequencySynthesizer
译文:
高速数字混合锁相环频率合成器
英文
中文
HighSpeedDigitalHybridPLLFrequencySynthesizer
Abstract:
TheconventionalPLL(Phaselockedloop)frequencysynthesizertakesalongswitchingtimebecauseoftheinherentclosed-loopstructure.
ThedigitalhybridPLL(DH-PLL)whichincludestheopenloopstructureintotheconventionalPLLsynthesizerhasbeenstudiedtoovercomethisproblem.
Itoperatesinhighspeed,butthehardwarecomplexityandpowerconsumptionareotherseriousproblemssincetheDLT(digitallook-uptable)isusuallyimplementedbytheROMwhichcontainsthetransfercharacteristicofVCO(voltagecontrolledoscillator).
ThispaperproposesanewDH-PLLusingaverysimpleDLT-replacementdigitallogicinsteadofthecomplexROM-typeDLT.
Also,atimingsynchronizationcircuitmakesthenegligibleovershootandmuchshortersettlingtimefortheultrafastswitchingspeed.
Also,thehardwarecomplexityandpowerconsumptiongetdecreasedtoabout28%,comparedwiththeconventionalDH-PLL.
KeyWords:
PLL,DLT,Frequencysynthesis
I.INTRODUCTION
Highspeedfrequencysynthesisisveryimportantandiswidelyusedintheelectronicandcommunicationsystemapplications.
In1999,El-Elaproposedthatadditionalsignalwhichisasynchronizedsaw-toothwaveformfromtheD/AconverterisinjectedintotheVCOinputoftheconventionalPLLfrequencysynthesizerforthehighspeedoperation[1].
However,itneedstheoptimalslopeanddurationateveryfrequencysynthesis.
Togetthehigh-speed,itisnecessarytopreparetheprecisesynchronizationofthecomplicateddesign.
In2001,H.G.RyuproposedasimplifiedstructureoftheDDFS(directdigitalfrequencysynthesizer)-drivenPLLforthehighswitchingspeed[2].
However,thereisaproblemthatthespeedofthewholesystemislimitedbyPLL.
Y.FouzarproposedaPLLfrequencysynthesizerofdualloopconfigurationusingfrequency-to-voltageconverter(FVC)[3].
IthasafastswitchingspeedbythePD(phasedetector),FVCusingoutputsignalofVCOandtheproposedcoarsetuningcontroller.
However,H/Wcomplexityisincreasedforthehighswitchingspeed.
Also,itshowsthefastswitchingcharacteristiconlywhentheFVCworkswell.
Anothermethodispre-tuningonewhichiscalledDH-PLLinthisstudy[4].
Ithasveryhighspeedswitchingproperty,butH/Wcomplexityandpowerconsumptionareincreasedduetodigitallook-uptable(DLT)whichisusuallyimplementedbytheROMincludingthetransfercharacteristicofVCO(voltagecontrolledoscillator).
Forthisreason,thispaperproposesatimingsynchronizationcircuitfortherapidfrequencysynthesisandaverysimpleDLTreplacementdigitallogicblockinsteadofthecomplexROMtypeDLTforhighspeedswitchingandlowpowerconsumption.
Also,therequisiteconditionissolvedintheproposedmethod.Thefastswitchingoperationateverythefrequencysynthesisprocessisverifiedbythecomputercircuitsimulation.
II.DH-PLLsynthesizer
AsshowninFig.1,theopen-loopsynthesizerisadirectfrequencysynthesistypethatVCOgeneratesthedesiredoutputbytheFCW(frequencycontrolword)inputfromtheD/Aconverter.
ThedigitalfrequencywordwhichisproducedfromtheROMtypeDLT(digitallook-uptable)containingtheVCOtransfercharacteristicgoesintoD/AconverterthatgeneratestheDCvaluecorrespondingtothedesiredVCOfrequency.
Fig.1.Open-loopfrequencysynthesizer.
TheDCvalueisalreadyfoundbythevoltage-frequencycharacteristicsofVCO.
Thisopen-loopfrequencysynthesizerhasfastswitchingspeed.
However,ithasthebigproblemsofstabilityandsensitivityduetotheinherentpropertiesoftheopenloopstructure.
Therefore,thissynthesizertypeisnotsoattractivethatthissynthesizerisnotwidelyused.
Fig.2.Closed-loopPLLfrequencysynthesizer.
InFig.2,FCW(frequencycontrolword)isthedivisionratiocommandforfrequencysynthesis.
Thisstructureisverypopularandexcellentintheaspectsofthestability,varietyandflexibility.
Also,thespuriousnoiseissmallerthanotherfrequencysynthesizer.
Ittakesthelongeracquisitiontimetojumpintoanewfrequencysothattheswitchingspeedislow.
Theswitchingtimegetslongerasthegenerationfrequencyspacingisincreased.
DH-PLLfrequencysynthesizerisshowninFig.3.
Fig.3.DH-PLLusingDLT(digitallook-uptable).
Theopen-loopstructureoftheDLTandDACiscombinedintotheconventionalPLLclosed-loopstructure.
IntheconventionalPLL,theoutputvoltageofLFisfedtotheVCO.
Onthecontrary,sumofDACoutputvoltageandtheLFoutputvoltagedrivestheVCOwheneverFCWischanged.
Therefore,unlikeconventionalPLL,DACoutputsthesteadystatedrivingvoltageateverynewFCWchangetimessothathighspeedfrequencyswitchingmaybepossible.
However,theDH-PLLhasaseriousproblemofthephasechangeateverynewfrequencysynthesis.
AsshowninFig.4,theovershootandthesettlingtimehaveatrade-offrelationshipbecausetheoutputofprogrammabledividermovesintootherpointafterthenewFCWstart,eventhoughsystemparametersarepreviouslyoptimized.
So,ithasalongsettlingtimeandtheswitchingspeedgetsdown.
Phasedetectorinputsare②,③waveformsofFig.4whichareusedforthecontrolvoltageofLF(loopfilter).
Therefore,therelationshipbetween②and③isfixeduntilanewFCWismade.
Fig.4.OperatingsignalofDH-PLL.
However,ifanewFCWistriggered,②waveformgoesdownthelow-state("0")inunexpectedplace,whichmeansavoltagechangestartofLF.
ThoughthereisasteadystatevoltagefromtheDAC,theovershoothappensforanewfrequencysynthesissothatsettlingprocesstakesalongtime.
LiketheconventionalPLL,theovershootandsettlingtimegetgreatlychangedforthewiderfrequencysynthesisspacing.
Inordertoovercomethisproblem,anewtimingsynchronizationcircuitisadditionallydesignedandthewholeDH-PLLstructureisshowninFig.5.
Fig.5.BlockdiagramofthenewproposedDH-PLL.
IV.Simulationresultsanddiscussion
Inthispaper,parametersoftable1andprocedureoftable2areusedtoverifytheswitchingfunctionoftheproposedDH-PLLcircuitstructure.
FCWisthedivisionratio.Fig.9and10aretheresultsofthecomputercircuitsimulations.
Divisionratiois8bitbinaryvalueandFCWchangesinevery1[msec].
ChangeofthedivisionratioshouldbemadeinthelinearregionofVCOtransfercurve.
InFig.10,theupperwaveformisinputdrivingvoltageofVCO,andthelowerisoutputvoltageofDAC.
AsshowninFig.10,thereareverysmallovershootandveryshortsettlingtimeinthefrequencysynthesistransitionprocessbecausetheinputtothephasedetectorissynchronizedwiththereferenceinputsignalirrespectiveofhowmanytheprogrammabledividercountstheVCOoutput.
OutputvoltageofDACis0[V]attheinitialstate.
Consequently,voltagefromDACandloopfilteroutputareaddedtodrivetheVCOsothatthedesiredfrequencymaybeobtained.
ItcanbeeasilyshownthattheinputdrivingvoltageofVCOisdifferentfromtheconventionalPLLclosed-loopstructureattheswitchingtimes.
ItisswiftlychangedbyoutputvoltageofDACandmovedintothesteadystatedrivingvoltageinaveryshortertimewheneverFCWvaries.
Fromtheseresults,itisshownthatDHPLLhasveryhighspeedswitchingfunction.
Also,wecancomparetheproposedDLT-replacementblockwiththeconventionalROMtypeDLTintheaspectsofthecircuitcomplexity.
V.Conclusion
Inthispaper,aDH-PLLsynthesizerusingsimpledigitallogiccircuitinsteadofROMtypeDLTblockisproposedtoovercomethecircuitcomplexityandpowerconsumptionoftheconventionalDH-PLL.
Infact,DLTblockisaburdenofhardwarecomplexityandtakesalongaccesstimetospeeddowntheswitchingoperation.
Inaddition,thereisanecessaryconditionthatthefirstfrequencycontrolwordshouldbesameattheinitialoperation.So,theproposedstructuresolvestherequisiteconditionandisverifiedbycomputersimulation.
Thehardwarecomplexityandpowerconsumptiongetsdecreasedtoabout28%,ascomparedwiththeconventionalDH-PLL.
FrequencysynthesizeroftheproposedDH-PLLstructurecanbeusedforthefastfrequencyhoppingsystem,electronicandcommunicationsystems.
REFERENCES
[1]El-Ela,M.A."HighspeedPLLfrequencysynthesizerwithsynchronousfrequencysweep,"NRSC'99.ProceedingsoftheSixteenthNational,pp.23-25,Feb.1999.
[2]H.G.Ryu,Y.Y.Kim,H.M.YuandS.B.Ryu,“DesignofDDFS-drivenPLLFrequencySynthesizerwithReducedComplexity,”IEEETransactionsonConsumerElectronics,Vol.47,No.1,Feb.2001.
[3]Fouzar,Y.,Sawan,M.,Savaria,Y."AnewfullyintegratedCMOSphase-lockedloopwithlowjitterandfastlocktime,"ISCAS2000Geneva.The2000IEEEInternationalSymposiumonCircuitsandSystems,Vol.2,pp.253-256,May2000.
[4]DavidM.Materna,“ALightweightFastHoppingSynthesizerForEHFSatelliteApplications,”MilitaryCommunicationsConference,MILCOM95,ConferenceRecord,IEEE,Vol.2,pp752-759,1995.
高速数字混合锁相环频率合成器
摘要:
传统的锁相环频率合成器需要很长的切换时间,因为其内在的闭环结构。
目前已经研发的一种数字混合锁相环来解决这一问题——在传统的锁相环频率合成器中加入开环结构。
它可以高速运行,但硬件复杂度和功耗是一个严重的问题,因为它的数字查找表(包含压控振荡器的传输特性)在ROM中频繁执行。
本文提出一种新的数字混合锁相环——使用一种简单的数字查找表代替复杂的ROM型数字查找表。
此外,定时同步电路使得环路超调量很小且建立时间短,从而保证了超高速切换速度。
同时,硬件复杂度和功耗比传统的数字混合锁相环(DH-PLL)大约降低28%。
关键词:
锁相环(PLL),数值查找表(DLT),频率合成
1简介
高速频率合成是一种非常重要的技术,被广泛地应用在电子和通信系统应用。
在19
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