外文翻译压控高频LC振荡器的设计Word文档格式.docx

外文翻译压控高频LC振荡器的设计Word文档格式.docx

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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±