高频压控振荡器外文翻译.docx
《高频压控振荡器外文翻译.docx》由会员分享,可在线阅读,更多相关《高频压控振荡器外文翻译.docx(9页珍藏版)》请在冰豆网上搜索。
高频压控振荡器外文翻译
VoltagecontroldesignofhighfrequencyLCoscillators
Student:
Pxxx,physicsandinformationengineeringcolleges
Instructor:
xxx,JianghanUniversity
Inrecentyears,withtherapiddevelopmentofwirelesscommunicationtechnology,makethemarketforrfintegratedcircuithashadahugedemand.Intherfcircuit,thevoltagecontroloscillation(VCO)occupiedaveryimportantposition.Withawiderangeofapplications.Intheearlystagesoftheradiotechnologydevelopment,itisusedtoproducehigh-frequencyintransmittercarriervoltage,Asaspecializedsuperheterodynereceiversinthemachineoscillator,besendingandreceivingequipmentbasiccomponents.Nowtheuseofoscillatorismoreandmorewidely.Forexample:
inradiocommunication,radio,andtelevisionequipmentusedtoproducetheneedofthecarrierandthemachineoscillationsignal;Intheelectronicmeasuringinstrumentsusedtoproduceallsortsoffrequencysinesignals,etc.
Definition
Oscillatorissimplystatedafrequencysource,usuallyinaphaselockloop.Detailedsaidisthatadevicedon'tneedthesignaltotheirownmotivation,DcpowercanbetransformedintoAcpower.Generallyfallintothepositivefeedbackandnegativeresistance.Theso-called"oscillating",Itsmeaningistoalludetoexchange,.Oscillatorincludesaneveroscillationtoprocessandfunctionofoscillation.Cancompletionfromdctoacpowertransformation,Thisdevicecanbecalled"oscillator".
Oscillatorworkingprinciple
LCcircuitconsistingofcapacitorsandinductors,electricfieldandtheconversionofmagneticenergyproductionprocessfreeoscillation.Tomaintaintheoscillationalsohasapositivefeedbackamplifiercircuit,theLCoscillatorisdividedintoatransformercoupledandthree-pointoscillator,manyapplicationsofquartzcrystalquartzcrystaloscillator,LCoscillatorwithanintegratedoperationalamplifier.Exactlythesamedevicecannotbeparametersinthestateofthepowerthemomentthetwotransistoroccursachange,thischangeduetoincreasinglystrongroleinthepositivefeedback,leadingtoreachatemporarysteadystate.Duringthetemporarysteadystatetoanothertransistorbycapacitancegraduallychargeconductionorclosedstateofthefliptoanothertemporarysteadystate.Thiscycleofformationofoscillation.
Theclassificationofoscillator
OscillatoraredividedintoRC,LCoscillatorsandcrystaloscillator,1.TheRCoscillatorUsetheRCnetworkasfrequencyselectivephaseshiftingnetworkiscalledRCsinusoidaloscillatorBelongtoaudiooscillator.2.LCoscillatorsUsetheLCoscillationloopasmoveandfrequencyselectivenetworkofPositivefeedbackoscillatoriscalledLCoscillators.LCoscillatorsclassification:
(1)transformercouplingSinglepipeLCsinusoidaloscillatordifferencetotheLCsinusoidaloscillator
(2)ThreepointpatternCondenserthreepointpatternoscillator,threepointtypeoscillator(3)TheimprovementofthreetypeClapposcillator,Seileroscillator(4)Thedifferenceoftubeoscillator3.CrystaloscillatorTheoscillationfrequencyoftheoscillatorbyquartzcrystalcontrolledoscillator.
Thetemperaturecoefficientoscillator
Temperaturecoefficientoscillatorreferstoanoscillator,itsoscillationfrequencyandtemperaturehaveaspecificrelationshipbetweenthedifferenttemperaturescorrespondingtodifferentoscillationfrequencies.Conversely,measuringtheoutputfrequencyoftheoscillator,wecanmeasurethetemperature.Hightemperaturecoefficientoscillator:
itsoscillationfrequencyisaffectedbytemperature,aslightchangeintemperature,thefrequencywillchangealot,thatistemperaturesensitive,andmoreforthetemperaturesensor.lowtemperaturecoefficientoscillator:
theoscillationfrequencytemperaturehaslittleeffect,evenifthetemperaturevariesgreatly,itsfrequencyisessentiallythesame.
Quartzcrystaloscillator
Quartzcrystaloscillatorandnon-temperaturecompensatedcrystaloscillators,temperaturecompensatedcrystaloscillator(TCXO),voltagecontrolledcrystaloscillator(VCXO),thermostaticallycontrolledcrystaloscillator(OCXO)anddigital/μpcompensatedcrystaloscillator(DCXO/MCXO)andothertypes.Amongthem,temperaturecompensatedcrystaloscillatoristhesimplestone,intheJapaneseIndustrialStandard(JIS),calledthestandardpackagecrystaloscillator(SPXO).NowSPXOexample,abriefoverviewofthestructureandworkingprincipleofthequartzcrystaloscillator.
Quartzcrystals,naturalandartificial,isanimportantpiezoelectriccrystalmaterials.Thequartzcrystalitselfisnotanoscillator,itisonlybymeansoftheactiveencouragementandpassivereactancenetworkbeforeoscillation.SPXOismainlycomposedofhighcrystalresonators(crystaloscillator)andfeedbackoscillationcircuitofqualityfactor(Q).Thequartzcrystaloscillatorisanimportantcomponentintheoscillator,thefrequencyofthecrystal(fundamentalfrequencyorthen-thharmonicfrequency)anditstemperaturecharacteristicsdependlargelyonthecuttingorientation.
Poleonthecrystaloscillatorboardtoimposeanalternatingvoltage,itwillcausethechiptoproducemechanicaldeformationvibration,thisphenomenonistheso-calledinversepiezoelectriceffect.Whentheappliedvoltagefrequencyisequaltothenaturalfrequencyofthecrystalresonator,piezoelectricresonator,resultinginmechanicaldeformationamplitudeincreasessuddenly.Withthemetalplatebetweentheelectrostaticcapacitance;L,andCisthepiezoelectricresonatorequivalentparameters;Ristheequivalentresistanceofthevibrationfrictionloss.Quartzcrystalresonators,thereisaseriesresonantfrequencyfos(1/2π),thereisalsoaparallelresonantfrequencyfop(1/2π).DuetoaverysmalldifferencebetweentheCo.C,fopandfos,andtheRωOL,theR1/ωOCresonantcircuitqualityfactorQisveryhigh(uptoseveralmillions),sothatofthequartzcrystalresonatortheoscillatorfrequencystabilityisveryhigh,upto10-12/day.QuartzcrystaloscillationfrequencycanapproximateinfosDepartment,canalsoworkaroundtheinfop,aquartzcrystaloscillatorcanbedividedintotwokindsoftheseriesandshunt.Quartzcrystalresonatoranditsequivalentcircuit,replacethecomponentsoftheLCoscillatorconstitutesaresonantcircuitinductance(L)andcapacitance(C),itiseasytounderstandtheworkingprincipleofthecrystaloscillator.
SPXOthetotalaccuracy(includinginitialaccuracyandtemperature,voltage,andloadchanges)canbeupto±25ppm.SPXOneithertemperaturecompensatedtemperaturecontrolmeasures,anditsfrequency-temperaturecharacteristicsalmostentirelydeterminedbythefrequency-temperaturecharacteristicsofquartzcrystaloscillator.Withintherangeof0~70℃SPXOfrequencystabilityistypically20~1000ppm,SPXOcanbeusedasaclockfrequencyoscillator.
Temperaturecompensatedcrystaloscillator(TCXO)
TCXOisgeneratedbytheambienttemperaturechangeofaquartzcrystaloscillatoroscillationfrequencychangereductionthroughadditionaltemperaturecompensationcircuitry.
1.TCXOtemperaturecompensation
InTCXOquartzcrystaloscillatorfrequencytemperaturedriftcompensationmethodofdirectcompensationandindirectcompensationaretwotypes:
directlycompensated
DirectcompensationTCXObythethermistorandthetemperaturecompensationcircuitcomposedofresistiveandcapacitivecomponentsintheoscillatorinserieswiththequartzcrystaloscillator.Changesintemperature,thethermistorresistanceandcrystalequivalentseriescorrespondingchangesinthevalueofthecapacitor,inordertooffsetorreducethetemperaturedriftoftheoscillationfrequency.Thecompensationcircuitissimple,lowercost,savingtheprintedcircuitboard(PCB)sizeandspaceforsmallandlow-voltagecurrentoccasion.However,whenthecrystaloscillatoraccuracyoflessthan±1pmm,directcompensationisnotappropriate.
IndirectCompensation
Indirectcompensationtypeisdividedintoanaloganddigitaltwotypes.AnalogIndirecttemperaturecompensationthermistortemperaturesensingelementcomposedofthetemperature-voltageconversioncircuitandthevoltageappliedtothecrystaloscillatorseriesonacrystaloscillatorconnectedinseriesvaractorcapacitancechangesnonlinearcrystaloscillatorfrequencydriftcompensation.Themethodofcompensationtoachievehighaccuracyof±0.5ppm,butrestrictedinthecaseoflowvoltagebelow3V.Indirecttemperaturecompensationofthedigitalplusatemperatureintheanalogcompensationcircuit-voltageconversioncircuitanalog/digital(A/D)converter,analogconvertdigital.TheActenablestheautomatictemperaturecompensationcrystaloscillatorfrequencystabilityisveryhigh,butthespecificcompensationcircuitismorecomplexandhighercostappliesonlytotheprecisionofbasestationsandradiostationsrequirements.
2.TCXOdevelopmentstatus
TCXObyleapsandboundsinthelastdecade,whichintheresearchanddevelopmentandproductionofprecisionTCXO,Japan'sleadinganddominantposition.Mainstreamproductsinthelate1970scarphoneTCXOvolumeofmorethan20reducedto0.4,TCXOdevicesofultra-smallvolumeofonly0.27.In30years,theTCXOvolumereducedbymorethan50timesoreven100times.BeijingceramicscompanyinJapanusingthereflowsolderingmethodofproductionofsurfacemountTCXOthicknessfrom4mmto2mm,rated90%oftheoscillationamplitudein4msafterthestartoftheoscillationcanbeachieved.Stone(KSS)GroupTCXOfrequencyrangeof2~80MHzstabilitywhenthetemperaturechangesfrom-10°Cto60°C±1ppmor±2ppm;digitalTCXOfrequencycoverageof0.2~90MHzfrequencystability±0.1pp