【本科优秀毕业设计】l波段接收机的设计

毕业设计论文L波段接收机的设计学院年级专业2003级电子信息工程学生姓名指导教师专业负责人答辩日期2007年6月24日毕业设计论文任务书学院里仁学院系级教学单位电子工程系学号学生姓名专业班级电子信息工程1班题目L波段接收机的设计课题来源实践主要内容对接收机的噪声、动态、增益的性能指标设计对宽带低噪声放大器、电调衰减器、ITHELOWINTERMEDIATEFREQUENCYPLANALTHOUGHMAYREMARKABLEREDUCENEEDSTHEPARTNUMBER，BUTTHEHIGHSYSTEMGAINSIGNSNOTEASYTOASSIGN，MOREOVERTHISKINDOFSTRUCTUREREQUESTHASTHEVERYHIGHMIRRORIMAGESUPPRESSIONBUTTHEHETERODYNEPLANMAYTHEVERYGOODSOLUTIONMIRRORIMAGEQUESTIONANDTHEHIGHGAINQUESTIONAFTERCARRIESONTHREEKINDOFPLANSMEASURING，WEUSETRADITIONALTHEHETERODYNESTRUCTURETOTAKETHECHANNELRECEIVERTHEPLANINORDERTOSOLVETHISTOBECONTRADICTORY，WEFINALLYHAVEUSEDTWOUNDERFREQUENCYCONVERSIONSUPERHETERODYNERECEIVERSPLANINTHISKINDOFSTRUCTURE，THERADIOFREQUENCYSIGNALTHATCOMESINFORMTHEANTENNAAFTERTHEFILTER，THELOWNOISEAMPLIFIER，AFTERTHEMIXINGBECOMESTHEFIRSTINTERMEDIATEFREQUENCYSIGNAL，FIRSTINSPIRESINTHISISAFIXTUREAFTERTHEINTERMEDIATEFREQUENCYSIGNALPASSESTHROUGHONCEMORETHEFILTERANDTHEENLARGEMENTSENDSINTHESECONDLEVELOFMIXER，CHANGESTHESIGNALTOTHESECONDINTERMEDIATEFREQUENCYSIGNAL，THEINTERMEDIATEFREQUENCYAMPLIFIERGAINALSOMAYCONTROL，WHENSYSTEMWORKTHEGAINCONTROLSIGNALTHESIGNALWHICHDEMODULATESBYTHEREARENDDSPBASISPRODUCESINABOVEGROUPCHANNEL，THESIGNALAFTER2MHZSEVENSTEPSELLIPTICFUNCTIONLCFILTERLNACARRIESONTHEENLARGEMENTTOTHESIGNAL，FROMTHREELEVELOFAGCREALIZATIONSYSTEMDYNAMIRANGETARGETREQUEST，FINALLYENLARGESAFTERWARDSTHESIGNALTOINTHEREQUESTLEVELOUTPUTSTHISGROUPCHANNELDOESNOTHAVEFREQUENCYCONVERSIONPROCESSING，BECAUSETHESIGNALINGFREQUENCYISLOWERTHAN2MHZ，MAYDIRECTLYCARRYONTOTHEOUTPUTSIGNALUSESTHEDIGITIZATION，THENCARRIESONBASEBANDPROCESSINGBYDSPTHISGROUPCHANNELMAINGUARANTEEDYNAMIRANGE，LINEAR，SENSITIVITYTARGETANDSOONSELECTIVITYFRONTENDUSESTHELOWNOISE，THEALTITUDE，HIGHINCREASESTHEFIELDEFFECTTUBETOTAKELNA，GUARANTEESTHECHANNELTHETOTALNOISEFACTORANDLINEARTHEAGCSTRUCTUREWITHFOLLOWINGGROUPCHANNELCONSISTENCY2MHZ30MHZCHANNELUSESTWOTIMESOFFREQUENCYCONVERSIONSUPERHETERODYNESTRUCTURES，THEFIRSTINTERMEDIATEFREQUENCYFORHIGHINTERMEDIATEFREQUENCY488MHZ，FRONTEDTHISKINDOFSTRUCTUREUNIONSIXGROUPOFASIANFREQUENCYMULTIPLICATIONBANDPASSFILTERMAYOBTAINTHEVERYGOODMIRRORIMAGETODAMPTHESYSTEMTOSATISFYTHESYSTEMTARGETREQUESTTHESIGNALFIRSTLOWLYINSERTSBY2M30MHZDAMAGESTHEFILTERTOTHEBELTOUTSIDETHESIGNALENERGYCARRIESONTHECERTAINSUPPRESSION，LNAISPUSHTHEPULLALTITUDESTRUCTURE，SELECTSTWOLOWNOISES，HIGHIP3，THEHIGHGAINFIELDEFFECTTUBECONSTITUTIONSUPPLEMENTARYSTRUCTUREENHANCESLINEARANDREDUCESTHEENTIREMACHINENOISE，SATISFIESTHESYSTEMTHESETWOTARGETSREQUESTAFTERLNAISAGROUPTHERESELECTWHICHCONSTITUTESBYSIXASIANFREQUENCYMULTIPLICATIONHIGHSELECTIVEBANDPASSLCFILTER，ENHANCESTHESYSTEMSELECTIVITYANDTHEANTIGAMBLINGABILITY，AFTERREDUCEINTHELEVELCHANNELDISORDERLYTHELEVEL，THERESELECTEDSIXTHROWSTHESWITCHBYTWOSINGLETOOLSTOCARRYONTHECONTROLCUTTHESIGNALDINEMIRAGEFROMREALIZESTHREETOFOURLEVELOFAGC，PULLEVENISINFRONTOFTHEFREQUENCYCONVERSIONTHESIGNALPOWERINTHEIDENTICALSTABLELEVEL，AFTERGUARANTEESTHEFREQUENCYCONVERSIONLINEARFIRSTLEVELOFAGCISTHEPINTUBEELECTRICITYADJUSTSTHEATTENUATORSSITUATIONAGC，THELATTERSEVERALLEVELSAREVGAAGCAFTERTHEDOUBLEBALANCEDMIXERTHREEFREQUENCYCONVERSIONENLARGESTHESIGNALTOTHEREQUESTLEVELLOSESLEAVESTHEFIRSTLEVELOFINTERMEDIATEFREQUENCYFILTERSELECTSTHERECTANGULARCOEFFICIENTTOBEGOOD，INTHEBELTRIPPLESMALLTABLESOUNDWAVESAWFILTERBANDWIDTH2MHZ，THESECONDINTERMEDIATEFREQUENCYFORCERAMICFILTERBANDWIDTH200KHZ，THETHIRDINTERMEDIATEFREQUENCYISTHE10KHZNARROWBANDCRYSTALFILTERASFORTHERECEIVERFREQUENCYSYNTHESIZER，CONSIDEREDTHESYSTEMREQUESTREALIZESTHE1HZFREQUENCYRESOLUTION，ATPRESENTONLYHASINTHEINFERIORFREQUENCYBANDFEASIBLEPLANUSESTHEDDSDIRECTNUMERALSYNTHESIS，WITHTHEDDSCHIPTOOKTHEFREQUENCYSYNTHESIZERTHECOREPART，PASSESSIDEANDSOONFREQUENCYMULTIPLICATIONTHETYPEREALIZESTHE1HZFREQUENCYRESOLUTIONWITH120MHZHIGHPURETHESTEADYCRYSTALOSCILLATORTOOKDDSTHEREFERENCEFREQUENCYSOURCE，FIRSTINSPIRESBECAUSEISONTHEFREQUENCYCONVERSIONREQUESTFREQUENCYISHIGHER，DDSDIRECTOUTPUTTHEUPPERFREQUENCYLIMITONLYCANARRIVETHEREFERENCEFREQUENCY04TIME，THEREFORENEEDSTOPASSTHROUGHTHEFREQUENCYMULTIPLICATION，OUTPUTS508MHZWHICHFIRSTINSPIRESNEEDS788MHZFREQUENCY，THELENGTHOFSTRIDEIS10KHZ，WHENSCANNINGTOOKTHICKLYSWEEPSPROVIDESSECONDTOINSPIRETHEFREQUENCYANOTHERDDSDIRECTOUTPUT，NEARBY381MHZCARRIESONBYTHE1HZ10HZLENGTHOFSTRIDETHINSWEEPSINORDERTOENHANCETHEMIXERBOOKTOINSPIRETHEMOUTHISOLATION，THESETWOGROUPSTHISINSPIRETHESIGNALTOWEAKENAFTERTHEENLARGEMENT，LIKETHISNOTONLYENHANCEDISOLATION，MOREOVERMAYTHISINSPIRETHESIGNALTOADJUSTTHEAPPROPRIATEBIGSIGNALTOCARRYONTHEMIXING，GUARANTEESMIXINGLINEARITYTHIRDINSPIRESFORFIXEDFREQUENCY10245MHZ，USESHIGHPURETHESTEADYCRYSTALOSCILLATORTHESYSTEMFREQUENCYCONTROL，CHANNELSSCANNING，THEFILTERSWITCHCUT，ASWELLASTHECHANNELCUTANDSOONTHEENTIREMACHINECONTROLREALIZESBYMCUTHROUGHTOTHEMCUPROGRAMMING，CONTROLSDDSBYTHEMCUOUTPUTTHEFCWFREQUENCYCONTROLWORD，THEFREQUENCYWHICHCAUSESDDSACCORDINGTOWHICHTOPREARRANGETHEREQUESTOUTPUTNEEDSTHECALCULATIONOFLINEARITYSYSTEMREQUESTSTHEENTIREMACHINEREALIZATIONTOOUTPUTTHREESTEPSINTERMEDIATIONTOMEASUREIP324DBM，THISTARGETWEIGHSASYSTEMLINEARITYMOSTIMPORTANTTARGET，MAINLYISDECIDEDINTHESYSTEMTHEAMPLIFIERANDMIXERLINEARALWAYSINPUTSTHREESTEPSINTERMEDIATIONQUANTITYFORMULAACCORDINGTOTHECASCADESYSTEMMAYCARRYONTHETHEORETICALCALCULATIONEACHLEVELOFACTIVESDEVICEINCLUDEDAMAGESCOMPONENTTHREESTEPSMUTUALLYTONEVALUESTHESYSTEMINTOSUBSTITUTETHEPREVIOUSTYPECOMPUTATION，MAYOBTAINTHESYSTEMINPUTENDALWAYSTOINPUTIP3THEVALUE，NEEDSSPECIALLYTOPAYATTENTION，USESINTHEPREVIOUSTYPECOMPUTATIONTHREESTEPSVALUETOHAVETOBEEACHCOMPONENTINPUTTHREESTEPSVALUE，INTHECOMPONENTMATERIALPRODUCESUSUALLYALLOUTPUTSTHREESTEPSVALUES，USESINTHEFORMULATOHAVETOSUBTRACTTHECOMPONENTTHEGAIN132121,NINIPGIPGIIMOREOVERMUSTCONVERTTHEACTUALPERFORMANCENUMBER，THEGAINALSOMUSTTRANSFORMINTOTHEACTUALMULTIPLE，CANNOTUSEADECIBELVALUETOCARRYONTHECOMPUTATION，AGAINWILLCALCULATETHEALWAYSINPUTTHREESTEPSPERFORMANCENUMBERSWILLTRANSFORMINTOTHELOGARITHMPERFORMANCENUMBERSYSTEMALWAYSIP3CALCULATESAGAINBASEDONTHUNDERTYPETHISFORMULACOMPUTATIONMAYSTRAIGHTTAKEOVERTHEUSEOFADECIBELVALUETOCARRYONTHECOMPUTATIONAFTERCOMPUTINGSYSTEMALWAYSIP327DBM24DBM，SATISFIESTHESYSTEMTARGETREQUESTCONCRETECOMPUTATIONTOBETEDIOUS，HEREONLYPRODUCESCOMPUTEDRESULTINSYSTEMMAJOREFFECTENTIREMACHINEIP3ISFIRSTLEVELOFLNA，THEMIXERANDLASTLEVELOFAMPLIFIERSLINEARTHEREFORETHETOPICINTHEDESIGN，FIRSTLEVELOFLNASELECTSOUTPUTSTHREESTEPSINTERMEDIATIONQUANTITYTOREACHASHIGHAS42DBMSUPERELEVATIONLINEARFET，THEMIXERSELECTSINPUTSTHREESTEPSFORTHE32DBMDOUBLEBALANCEDALTITUDEMIXER，INTHECHANNELAMPLIFIERSELECTSTHREESTEPSTOBEHIGHERTHANTHE30DBMAMPLIFYINGTUBESYSTEMTHEFRONTENDCHANNELCUTSINGLEPOLEDOUBLETHROWSWITCHSELECTSHITTITECORPORATIONHMC190MS8，IP350DBM，INSERTSDAMAGESONLY04DB，THESINGLETOOLWHICHTHEFILTERCUTSSIXTHROWSTHESWITCHTOUSLEHMC252QS24，IP346DBM，THEIRACTUALINFLUENCEISVERYSMALL，MAYIGNOREINFIRSTLEVELOFAGCTHEELECTRICITYADJUSTSTHEATTENUATORTHEPINTUBETOSELECTTHREESTEPSINTERSMODULATIONQUANTITYTOBEHIGHERTHAN60DBM，ALSOMAYNEGLECTTHEHIGHSENSITIVITYREALIZATIONRELIESONENTIREMACHINENOISEFACTORREDUCINGTHESYSTEMNOISECOEFFICIENTMAYCALCULATEBASEDONTHECASCADESYSTEMTOTALNOISEFACTORFORMULASIMILARLY，WHENCOMPUTATIONNEEDSALLLEVELSOFGAINSCONVERSIONFURTHERREALITYMULTIPLE，THETOTALNOISEFACTORWHICHWILLCALCULATEAGAINTOCONVERTADECIBELVALUEMAYSEEFROMTHEANALYSISFORMULA，IFTHECASCADESYSTEMFIRSTLGIPIN,31121FGFLEVELFORISINCREASINGTHECOMPONENT，GENERALLYISINRECEIVERLNA，IFITSGAINISG1ENOUGHBIG，THENINTHEFORMULATHEDENOMINATORWILLCONTAING1THEBEHINDITEMTOTHETOTALNOISEFACTORCONTRIBUTIONVERYSMALL，BASICWILLBEALLOWEDTONEGLECT，THENTHEENTIREMACHINENOISEFACTORONWILLBEBASICISTHELNANOISEFACTORADDSONINFRONTOFLNAWILLHAVEDAMAGESTHECOMPONENTINSERTSDAMAGESTHEREFORE，INRECEIVERLOWNOISEDESIGNTIME，FIRSTLEVELOFLNADESIGNESPECIALLYESSENTIAL，AFTERITSNOISEFACTORSHOULDASFARASPOSSIBLESMALLALSOTHEGAINMUSTTHEENOUGHBIGSUPPRESSIONTHELEVELNOISECONTRIBUTION，MOREOVERINFRONTOFTHELNAELECTRICCIRCUITINSERTSDAMAGESSHOULDBEASFARASPOSSIBLESMALLINFRONTOFTHISPROJECTLEVELSPDTSELECTSHITTITECORPORATIONLOWLYTOINSERTDAMAGESSWITCHHMC190MS8，INSERTSDAMAGESONLYIS04DB，IP350DBM，THEFIRSTLEVELOFLNANOISEFACTORIS12DB，THEGAINIS18DB，INFRONTOFLNA2MHZ30MHZSEVENSTEPSELLIPTICFUNCTIONFILTERINSERTSDAMAGESIS05DB，THECOMPUTATIONMAYRESULTINTHETOTALNOISEFACTORIS3DBACCORDINGTOSYSTEMSENSITIVITYFORMULAS174DBMNF10LOGBKSNKTHEACTUALCENTERUPPERLIMITMAYBEBIGGESTBYTHERECEIVEFUNCTIONRECEIVEANTISTOPSUPTHESIGNALTODETERMINETHAT，THELOWERLIMITDETERMINEDBYTHESYSTEMSENSITIVITY，BECAUSEINDESIGNTIME，INORDERTOENHANCERECEIVESTHEBIGSIGNALABILITY，JOINEDLEVELOFFUNCTIONSELECTRICCIRCUITSINFRONTENDADDTOBEPOSSIBLETOCUTTHEWEAKENELECTRICCIRCUIT，WHENSIGNALOVERSIZEDWASALLOWEDTOCUTTHEFIXEDWEAKEN，BUTWHENSMALLSIGNALNOWEAKENDIRECTLYPASSED，THEREFOREGREATLYENHANCEDTHESYSTEMDYNAMIRANGEUPPERLIMITUNIFIESTHREELEVELOFAGCTOBEALLOWEDTOREALIZEISBIGGERTHAN130DBTHEDYNAMIRANGESYSTEMNONMIXEDDISPERSESDYNAMIRANGESFDRALSOISWEIGHSTHESYSTEMOVERALLPERFORMANCETHEIMPORTANTTARGET，ISREFERSTOTHERECEIVERINPUTSIGNALFROMTOSURPASSNOISETHRESHOLD3DBPLACE，NAMELYMDS，TOHASNTHADTHREESTEPSINTERMEDIATIONMIXEDDISPERSESSOUNDSPOTPLACEBETWEENPOWERDYNAMIRANGENAMELYSFDR23IP3NF10LOGB171DBM95DBCONCRETEAGCREALIZATIONINNEXTSYSTEMREALIZATIONDETAILEDELABORATIONTHEMIRRORIMAGESUPPRESSIONANDTHEINTERMEDIATEFREQUENCYSUPPRESSIONTARGETSYSTEMDESIGNISTWOFREQUENCYCONVERSIONSUPERHETERODYNESTRUCTURES，FIRSTTIMEFORONFREQUENCYCONVERSION，TRANSFORMSTHESIGNALINGFREQUENCYTOHIGHINTERMEDIATEFREQUENCY488MHZON，THEGOALISFORENHANCETHEMIRRORIMAGESUPPRESSIONTHEMIRRORIMAGEFREQUENCYISTHESIGNALINGFREQUENCYTAKETHISINSPIRESTHEFREQUENCYSTHEAXISOFSYMMETRYMIRRORIMAGE，WHENTHESIGNALFREQUENCYBANDIES2MHZ30MHZ，FIRSTINSPIRESTHERANGEOFVARIATIONIS508MHZ788MHZTHENTHEMIRRORIMAGEFREQUENCYBANDIS996MHZ1276MHZ，FARISHIGHERTHANRECEIVERFIRSTHIGHTHISINSPIRESTHEFREQUENCY，THEREFOREINTHERECEIVEREACHLEVELOFFILTERSALLHAVEABETTERSUPPRESSIONTOTHEMIRRORIMAGEFREQUENCYALSOFRONTENDINPUTSLEVEL2MHZ30MHZFILTERNOTONLYHASTHESUPPRESSIONTOTHEMIRRORIMAGEFREQUENCY，MOREOVERALSOHASABETTORSUPPRESSIONTOFIRSTINTERMEDIATEFREQUENCY488MHZINORDERTOFURTHERENHANCESTHEMIRRORIMAGESUPPRESSIONANDTHEINTERMEDIATEFREQUENCYSUPPRESSIONALSOCANBETTERREDUCETHEINTERMODULATIONCAUSESSIMULTANEOUSLYTOENTERTHEMIXERDIMINUTIONINNUMBER，AFTERFIRSTLEVELOFLNAHASJOINEDTHEPRESELECTOR，BANDPASSFILTER，FREQUENCYBANDDIVISIONASFOLLOWS23MHZ，35MHZ，58MHZ，813MHZ，1320MHZ，2030MHZ，THEASIANFREQUENCYMULTIPLICATIONDESIGNINFORREDUCETHEINTERMEDIATION，MAYELIMINATETWOSTEPSTODISTORTDISTORTSTOTHREESTEPSALSOHASTHECERTAINSUPPRESSIONABILITYTHROUGHTOTHECHANNELINTHEFILTERCAREFULDESIGN，UNIFIESTHERECEIVERHIGHINTERMEDIATEFREQUENCYSUPERHETERODYNESTRUCTURETOBEALLOWEDTOOBTAINSATISFIESTHEDEPARTMENTTHESERIESREQUEST90DBINTERMEDIATEFREQUENCYANDTHEMIRRORIMAGEDAMPTHESYSTEMTARGETREQUESTINTHECHANNELAMPLIFIERANDTHEMIXERALONGWITHTHEELECTRONICDEVICECRAFTUNCEASINGPROGRESS，ENLARGETHECOMPONENTDEVELOPSINTHEINTEGRATIONRATEANDTHEVERSATILITYEXTREMELYRAPIDLYCAUSESTHEDESIGNANDTHEUSEGREATLYASSIMPLIFIESATPRESENTTHEGENERALAMPLIFIERNOWWORKEDTHEFREQUENCYBANDTOBEALLOWEDTOACHIEVECOVERSDC4GHZ，ALREADYHADMAYCOVERDC10GHZTHEMONOLITHICAMPLIFYINGTUBEINTHEPERFORMANCE，THELOWNOISELNANOISEFACTORHASALREADYACHIEVEDBELOW05DB，ANDCANWORKTOTHESWAVEBANDALTITUDEAMPLIFYINGTUBEP1DBMAYACHIEVE30DBM，IP3MAYAPPROACH50DBMASFORGAIN，SPECIALPURPOSEENLARGEMENTMODULEMODULETHEGAINMAYSURPASSASTRUCTUREDIAGRAMTHISLEVELOFRADIOFREQUENCIESLNANOTONLYISTHESYSTEMALTITUDEREALIZATIONKEY，ALSOISTHESYSTEMHIGHSENSITIVITYREALIZATIONKEYISATIFINTHEPLANPROOFSTATESINSERTSINTHISLEVELOFBEFOREDAMAGESTHEDETERMINATIONINTHESITUATION，THISLEVELNOISEFACTORANDTHEGAINHADBASICALLYDETERMINEDTHESYSTEMTOTALNOISEFACTOR，ALSOTHESYSTEMTOTALNOISEFACTORBASICALLYISFRONTTHELEVELINSERTSDAMAGESWITHTHISLEVELOFNOISEFACTORSUMMUSTREALIZETHEHIGHSENSITIVITY，THENECESSITYREQUESTSTHESYSTEMNOISECOEFFICIENTTOBELOW，THEFIRSTLEVELINSERTSDAMAGESASFARASPOSSIBLEINTHESMALLSITUATION，ONLYHASTAKESTHEMEASURETOREDUCETHISLEVELOFNOISEFACTORTHETOPICREALIZESINTHISUNIT，BESIDESSELECTSTHENOISEFACTORISONLY12DBFET，HASUSEDPUSHINTHEELECTRICCIRCUITSTRUCTURETHEPULLSTRUCTURE，THISKINDOFSTRUCTUREHASNEXTTWOREMARKABLECHARACTERISTICS1ENHANCESSYSTEMLINEARITYTHERFINPUTSIGNALDIVISIONFORBUTTWOEACHGROUPSIGNALPOWERFORLISTTUBETHESTRUCTUREONEHALF，NAMELYENHANCED3DBIP3ANDBECAUSEABOUTTHESUPPLEMENTARYSTRUCTURETWOGROUPSSIGNALSDIFFER180，SEPARATELYENLARGESSYNTHESISAGAIN，THEORETICALLYMAYCOUNTERBALANCEPARTNERTIMEOVERTONETHECOMPONENTELIMINATEDTWODISTORTIONSENHANCESTHESYSTEMTHENOISEPERFORMANCETHESIGNALSUPPLEMENTARYSTRUCTUREWHILECOUNTERBALANCEDAHALFHARMONICCOMPONENTAFTERPUSHTHEPULLALSOTOCOUNTERBALANCEAHALFNOISE，THEREFOREGREATLYENHANCEDREDUCEDENTEREDTHESYSTEMTHENOISEENERGY2ACTUALDEBUGSTHISLEVELOFELECTRICCIRCUITS，WANTSSTRICTLYINTHESTRUCTURESYMMETRICAL，THEFETDIRECTCURRENTOPERATINGPOINTMUSTCOMPLETELYCONSISTENT，WHENDEBUGGINGFULLYWANTSMAINLYTOARRIVETHISPOINT，THEDIRECTCURRENTOPERATINGPOINTSLIGHTLYHASTHEDIFFERENCETWOGROUPSSIGNALSPUTMASSIVELYAREDIFFERENT，AFTERTHESIGNALSYNTHESISINCREASESCANREDUCE，THEDISTORTIONCHANGESINABIGWAYCARRIESONTHESTRICTINPUTOUTPUTPORTMATCHTOTHEAMPLIFIERTHEUNBALANCECANCAUSETHESYSTEMGAINSAGTODROP，CAUSESTHESYSTEMNOISECOEFFICIENTTOINCREASE，THESENSITIVITYDROPSTHISGROUPCHANNELOPERATINGFREQUENCYIS2MHZ30MHZBECAUSECHOOSESTHECOMPONENTFREQUENCYINFLUENCEISBETTER，THEFREQUENCYLOWENDANDTHEHIGHENDGAINCHANGEISNOTBIG，THISLEVELOFACTUALGAINSARE1618DBINSWITCHCUTCHOICERESELECTEDFILTERPARTITIONCARRIESONTHEFILTER2MHZ30MHZTHEGOALISFORFURTHERENHANCESTHERECEIVERTHEMIRRORIMAGETODAMPTHESYSTEMEACHFILTERBANDWIDTHISSMALLERTHANFREQUENCYMULTIPLICATIONTHUSREDUCESENTERSTHECHANNELTHESIGNALTOCARRYONTHEINTERMEDIATIONQUANTITYTHESYSTEMMIRRORIMAGEDAMPSTHESYSTEMTARGETREQUESTTOBEEXTREMELYHIGH，FOR90DB，THEREFOREDESIGNSTHESESIXBANDPASSFILTERWITHTHEELLIPTICFUNCTIONLAW，THEELLIPTICFUNCTIONDESIGNISINTHEFILTERDESIGNMETHODTHEEDGESTEEPEST，RECTANGULARCOEFFICIENTHIGHEST，ALSOINSERTSDAMAGESVERYSLIGHTLY，BELTSUPPRESSIONISBETTERTHUSOBTAINSHIGHERMIRRORIMAGETODAMPTHESYSTEM，UNIFIESHIGHTHISINSPIRESONTHEFREQUENCYCONVERSIONRECEIVERSTRUCTUREANDTHEINTERMEDIATEFREQUENCYFILTERTOTHEMIRRORIMAGEFREQUENCYSUPPRESSIONMAYTHEBETTERSATISFIEDSYSTEM90DBMIRRORIMAGESUPPRESSIONTARGETIFSELECTSHASTHELATENTSTABILITYREGIONTHEAMPLIFIERTHENCARRIESONWHENTHEHIGHERWORKFREQUENCYBANDTOITTHEPORTMATCHESMUSTAVOIDASFARASPOSSIBLELATENTISUNSTABLE，REDUCESOCCURSFROMVIOLENTPOSSIBILITYINTHECHANNELTHEPRESENTMORECOMMONLYUSEDENLARGEMENTCOMPONENTISTHEMMIC