畢業(yè)設(shè)計(jì)論文L波段接收機(jī)的設(shè)計(jì)學(xué)院年級(jí)專業(yè)2003級(jí)電子信息工程學(xué)生姓名指導(dǎo)教師專業(yè)負(fù)責(zé)人答辯日期2007年6月24日畢業(yè)設(shè)計(jì)論文任務(wù)書學(xué)院里仁學(xué)院系級(jí)教學(xué)單位電子工程系學(xué)號(hào)學(xué)生姓名專業(yè)班級(jí)電子信息工程1班題目L波段接收機(jī)的設(shè)計(jì)課題來源實(shí)踐主要內(nèi)容對(duì)接收機(jī)的噪聲、動(dòng)態(tài)、增益的性能指標(biāo)設(shè)計(jì)對(duì)寬帶低噪聲放大器、電調(diào)衰減器、ITHELOWINTERMEDIATEFREQUENCYPLANALTHOUGHMAYREMARKABLEREDUCENEEDSTHEPARTNUMBER，BUTTHEHIGHSYSTEMGAINSIGNSNOTEASYTOASSIGN，MOREOVERTHISKINDOFSTRUCTUREREQUESTHASTHEVERYHIGHMIRRORIMAGESUPPRESSIONBUTTHEHETERODYNEPLANMAYTHEVERYGOODSOLUTIONMIRRORIMAGEQUESTIONANDTHEHIGHGAINQUESTIONAFTERCARRIESONTHREEKINDOFPLANSMEASURING，WEUSETRADITIONALTHEHETERODYNESTRUCTURETOTAKETHECHANNELRECEIVERTHEPLANINORDERTOSOLVETHISTOBECONTRADICTORY，WEFINALLYHAVEUSEDTWOUNDERFREQUENCYCONVERSIONSUPERHETERODYNERECEIVERSPLANINTHISKINDOFSTRUCTURE，THERADIOFREQUENCYSIGNALTHATCOMESINFORMTHEANTENNAAFTERTHEFILTER，THELOWNOISEAMPLIFIER，AFTERTHEMIXINGBECOMESTHEFIRSTINTERMEDIATEFREQUENCYSIGNAL，F(xiàn)IRSTINSPIRESINTHISISAFIXTUREAFTERTHEINTERMEDIATEFREQUENCYSIGNALPASSESTHROUGHONCEMORETHEFILTERANDTHEENLARGEMENTSENDSINTHESECONDLEVELOFMIXER，CHANGESTHESIGNALTOTHESECONDINTERMEDIATEFREQUENCYSIGNAL，THEINTERMEDIATEFREQUENCYAMPLIFIERGAINALSOMAYCONTROL，WHENSYSTEMWORKTHEGAINCONTROLSIGNALTHESIGNALWHICHDEMODULATESBYTHEREARENDDSPBASISPRODUCESINABOVEGROUPCHANNEL，THESIGNALAFTER2MHZSEVENSTEPSELLIPTICFUNCTIONLCFILTERLNACARRIESONTHEENLARGEMENTTOTHESIGNAL，F(xiàn)ROMTHREELEVELOFAGCREALIZATIONSYSTEMDYNAMIRANGETARGETREQUEST，F(xiàn)INALLYENLARGESAFTERWARDSTHESIGNALTOINTHEREQUESTLEVELOUTPUTSTHISGROUPCHANNELDOESNOTHAVEFREQUENCYCONVERSIONPROCESSING，BECAUSETHESIGNALINGFREQUENCYISLOWERTHAN2MHZ，MAYDIRECTLYCARRYONTOTHEOUTPUTSIGNALUSESTHEDIGITIZATION，THENCARRIESONBASEBANDPROCESSINGBYDSPTHISGROUPCHANNELMAINGUARANTEEDYNAMIRANGE，LINEAR，SENSITIVITYTARGETANDSOONSELECTIVITYFRONTENDUSESTHELOWNOISE，THEALTITUDE，HIGHINCREASESTHEFIELDEFFECTTUBETOTAKELNA，GUARANTEESTHECHANNELTHETOTALNOISEFACTORANDLINEARTHEAGCSTRUCTUREWITHFOLLOWINGGROUPCHANNELCONSISTENCY2MHZ30MHZCHANNELUSESTWOTIMESOFFREQUENCYCONVERSIONSUPERHETERODYNESTRUCTURES，THEFIRSTINTERMEDIATEFREQUENCYFORHIGHINTERMEDIATEFREQUENCY488MHZ，F(xiàn)RONTEDTHISKINDOFSTRUCTUREUNIONSIXGROUPOFASIANFREQUENCYMULTIPLICATIONBANDPASSFILTERMAYOBTAINTHEVERYGOODMIRRORIMAGETODAMPTHESYSTEMTOSATISFYTHESYSTEMTARGETREQUESTTHESIGNALFIRSTLOWLYINSERTSBY2M30MHZDAMAGESTHEFILTERTOTHEBELTOUTSIDETHESIGNALENERGYCARRIESONTHECERTAINSUPPRESSION，LNAISPUSHTHEPULLALTITUDESTRUCTURE，SELECTSTWOLOWNOISES，HIGHIP3，THEHIGHGAINFIELDEFFECTTUBECONSTITUTIONSUPPLEMENTARYSTRUCTUREENHANCESLINEARANDREDUCESTHEENTIREMACHINENOISE，SATISFIESTHESYSTEMTHESETWOTARGETSREQUESTAFTERLNAISAGROUPTHERESELECTWHICHCONSTITUTESBYSIXASIANFREQUENCYMULTIPLICATIONHIGHSELECTIVEBANDPASSLCFILTER，ENHANCESTHESYSTEMSELECTIVITYANDTHEANTIGAMBLINGABILITY，AFTERREDUCEINTHELEVELCHANNELDISORDERLYTHELEVEL，THERESELECTEDSIXTHROWSTHESWITCHBYTWOSINGLETOOLSTOCARRYONTHECONTROLCUTTHESIGNALDINEMIRAGEFROMREALIZESTHREETOFOURLEVELOFAGC，PULLEVENISINFRONTOFTHEFREQUENCYCONVERSIONTHESIGNALPOWERINTHEIDENTICALSTABLELEVEL，AFTERGUARANTEESTHEFREQUENCYCONVERSIONLINEARFIRSTLEVELOFAGCISTHEPINTUBEELECTRICITYADJUSTSTHEATTENUATORSSITUATIONAGC，THELATTERSEVERALLEVELSAREVGAAGCAFTERTHEDOUBLEBALANCEDMIXERTHREEFREQUENCYCONVERSIONENLARGESTHESIGNALTOTHEREQUESTLEVELLOSESLEAVESTHEFIRSTLEVELOFINTERMEDIATEFREQUENCYFILTERSELECTSTHERECTANGULARCOEFFICIENTTOBEGOOD，INTHEBELTRIPPLESMALLTABLESOUNDWAVESAWFILTERBANDWIDTH2MHZ，THESECONDINTERMEDIATEFREQUENCYFORCERAMICFILTERBANDWIDTH200KHZ，THETHIRDINTERMEDIATEFREQUENCYISTHE10KHZNARROWBANDCRYSTALFILTERASFORTHERECEIVERFREQUENCYSYNTHESIZER，CONSIDEREDTHESYSTEMREQUESTREALIZESTHE1HZFREQUENCYRESOLUTION，ATPRESENTONLYHASINTHEINFERIORFREQUENCYBANDFEASIBLEPLANUSESTHEDDSDIRECTNUMERALSYNTHESIS，WITHTHEDDSCHIPTOOKTHEFREQUENCYSYNTHESIZERTHECOREPART，PASSESSIDEANDSOONFREQUENCYMULTIPLICATIONTHETYPEREALIZESTHE1HZFREQUENCYRESOLUTIONWITH120MHZHIGHPURETHESTEADYCRYSTALOSCILLATORTOOKDDSTHEREFERENCEFREQUENCYSOURCE，F(xiàn)IRSTINSPIRESBECAUSEISONTHEFREQUENCYCONVERSIONREQUESTFREQUENCYISHIGHER，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，F(xiàn)IRSTLEVELOFLNASELECTSOUTPUTSTHREESTEPSINTERMEDIATIONQUANTITYTOREACHASHIGHAS42DBMSUPERELEVATIONLINEARFET，THEMIXERSELECTSINPUTSTHREESTEPSFORTHE32DBMDOUBLEBALANCEDALTITUDEMIXER，INTHECHANNELAMPLIFIERSELECTSTHREESTEPSTOBEHIGHERTHANTHE30DBMAMPLIFYINGTUBESYSTEMTHEFRONTENDCHANNELCUTSINGLEPOLEDOUBLETHROWSWITCHSELECTSHITTITECORPORATIONHMC190MS8，IP350DBM，INSERTSDAMAGESONLY04DB，THESINGLETOOLWHICHTHEFILTERCUTSSIXTHROWSTHESWITCHTOUSLEHMC252QS24，IP346DBM，THEIRACTUALINFLUENCEISVERYSMALL，MAYIGNOREINFIRSTLEVELOFAGCTHEELECTRICITYADJUSTSTHEATTENUATORTHEPINTUBETOSELECTTHREESTEPSINTERSMODULATIONQUANTITYTOBEHIGHERTHAN60DBM，ALSOMAYNEGLECTTHEHIGHSENSITIVITYREALIZATIONRELIESONENTIREMACHINENOISEFACTORREDUCINGTHESYSTEMNOISECOEFFICIENTMAYCALCULATEBASEDONTHECASCADESYSTEMTOTALNOISEFACTORFORMULASIMILARLY，WHENCOMPUTATIONNEEDSALLLEVELSOFGAINSCONVERSIONFURTHERREALITYMULTIPLE，THETOTALNOISEFACTORWHICHWILLCALCULATEAGAINTOCONVERTADECIBELVALUEMAYSEEFROMTHEANALYSISFORMULA，IFTHECASCADESYSTEMFIRSTLGIPIN,31121FGFLEVELFORISINCREASINGTHECOMPONENT，GENERALLYISINRECEIVERLNA，IFITSGAINISG1ENOUGHBIG，THENINTHEFORMULATHEDENOMINATORWILLCONTAING1THEBEHINDITEMTOTHETOTALNOISEFACTORCONTRIBUTIONVERYSMALL，BASICWILLBEALLOWEDTONEGLECT，THENTHEENTIREMACHINENOISEFACTORONWILLBEBASICISTHELNANOISEFACTORADDSONINFRONTOFLNAWILLHAVEDAMAGESTHECOMPONENTINSERTSDAMAGESTHEREFORE，INRECEIVERLOWNOISEDESIGNTIME，F(xiàn)IRSTLEVELOFLNADESIGNESPECIALLYESSENTIAL，AFTERITSNOISEFACTORSHOULDASFARASPOSSIBLESMALLALSOTHEGAINMUSTTHEENOUGHBIGSUPPRESSIONTHELEVELNOISECONTRIBUTION，MOREOVERINFRONTOFTHELNAELECTRICCIRCUITINSERTSDAMAGESSHOULDBEASFARASPOSSIBLESMALLINFRONTOFTHISPROJECTLEVELSPDTSELECTSHITTITECORPORATIONLOWLYTOINSERTDAMAGESSWITCHHMC190MS8，INSERTSDAMAGESONLYIS04DB，IP350DBM，THEFIRSTLEVELOFLNANOISEFACTORIS12DB，THEGAINIS18DB，INFRONTOFLNA2MHZ30MHZSEVENSTEPSELLIPTICFUNCTIONFILTERINSERTSDAMAGESIS05DB，THECOMPUTATIONMAYRESULTINTHETOTALNOISEFACTORIS3DBACCORDINGTOSYSTEMSENSITIVITYFORMULAS174DBMNF10LOGBKSNKTHEACTUALCENTERUPPERLIMITMAYBEBIGGESTBYTHERECEIVEFUNCTIONRECEIVEANTISTOPSUPTHESIGNALTODETERMINETHAT，THELOWERLIMITDETERMINEDBYTHESYSTEMSENSITIVITY，BECAUSEINDESIGNTIME，INORDERTOENHANCERECEIVESTHEBIGSIGNALABILITY，JOINEDLEVELOFFUNCTIONSELECTRICCIRCUITSINFRONTENDADDTOBEPOSSIBLETOCUTTHEWEAKENELECTRICCIRCUIT，WHENSIGNALOVERSIZEDWASALLOWEDTOCUTTHEFIXEDWEAKEN，BUTWHENSMALLSIGNALNOWEAKENDIRECTLYPASSED，THEREFOREGREATLYENHANCEDTHESYSTEMDYNAMIRANGEUPPERLIMITUNIFIESTHREELEVELOFAGCTOBEALLOWEDTOREALIZEISBIGGERTHAN130DBTHEDYNAMIRANGESYSTEMNONMIXEDDISPERSESDYNAMIRANGESFDRALSOISWEIGHSTHESYSTEMOVERALLPERFORMANCETHEIMPORTANTTARGET，ISREFERSTOTHERECEIVERINPUTSIGNALFROMTOSURPASSNOISETHRESHOLD3DBPLACE，NAMELYMDS，TOHASNTHADTHREESTEPSINTERMEDIATIONMIXEDDISPERSESSOUNDSPOTPLACEBETWEENPOWERDYNAMIRANGENAMELYSFDR23IP3NF10LOGB171DBM95DBCONCRETEAGCREALIZATIONINNEXTSYSTEMREALIZATIONDETAILEDELABORATIONTHEMIRRORIMAGESUPPRESSIONANDTHEINTERMEDIATEFREQUENCYSUPPRESSIONTARGETSYSTEMDESIGNISTWOFREQUENCYCONVERSIONSUPERHETERODYNESTRUCTURES，F(xiàn)IRSTTIMEFORONFREQUENCYCONVERSION，TRANSFORMSTHESIGNALINGFREQUENCYTOHIGHINTERMEDIATEFREQUENCY488MHZON，THEGOALISFORENHANCETHEMIRRORIMAGESUPPRESSIONTHEMIRRORIMAGEFREQUENCYISTHESIGNALINGFREQUENCYTAKETHISINSPIRESTHEFREQUENCYSTHEAXISOFSYMMETRYMIRRORIMAGE，WHENTHESIGNALFREQUENCYBANDIES2MHZ30MHZ，F(xiàn)IRSTINSPIRESTHERANGEOFVARIATIONIS508MHZ788MHZTHENTHEMIRRORIMAGEFREQUENCYBANDIS996MHZ1276MHZ，F(xiàn)ARISHIGHERTHANRECEIVERFIRSTHIGHTHISINSPIRESTHEFREQUENCY，THEREFOREINTHERECEIVEREACHLEVELOFFILTERSALLHAVEABETTERSUPPRESSIONTOTHEMIRRORIMAGEFREQUENCYALSOFRONTENDINPUTSLEVEL2MHZ30MHZFILTERNOTONLYHASTHESUPPRESSIONTOTHEMIRRORIMAGEFREQUENCY，MOREOVERALSOHASABETTORSUPPRESSIONTOFIRSTINTERMEDIATEFREQUENCY488MHZINORDERTOFURTHERENHANCESTHEMIRRORIMAGESUPPRESSIONANDTHEINTERMEDIATEFREQUENCYSUPPRESSIONALSOCANBETTERREDUCETHEINTERMODULATIONCAUSESSIMULTANEOUSLYTOENTERTHEMIXERDIMINUTIONINNUMBER，AFTERFIRSTLEVELOFLNAHASJOINEDTHEPRESELECTOR，BANDPASSFILTER，F(xiàn)REQUENCYBANDDIVISIONASFOLLOWS23MHZ，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，F(xiàn)OR90DB，THEREFOREDESIGNSTHESESIXBANDPASSFILTERWITHTHEELLIPTICFUNCTIONLAW，THEELLIPTICFUNCTIONDESIGNISINTHEFILTERDESIGNMETHODTHEEDGESTEEPEST，RECTANGULARCOEFFICIENTHIGHEST，ALSOINSERTSDAMAGESVERYSLIGHTLY，BELTSUPPRESSIONISBETTERTHUSOBTAINSHIGHERMIRRORIMAGETODAMPTHESYSTEM，UNIFIESHIGHTHISINSPIRESONTHEFREQUENCYCONVERSIONRECEIVERSTRUCTUREANDTHEINTERMEDIATEFREQUENCYFILTERTOTHEMIRRORIMAGEFREQUENCYSUPPRESSIONMAYTHEBETTERSATISFIEDSYSTEM90DBMIRRORIMAGESUPPRESSIONTARGETIFSELECTSHASTHELATENTSTABILITYREGIONTHEAMPLIFIERTHENCARRIESONWHENTHEHIGHERWORKFREQUENCYBANDTOITTHEPORTMATCHESMUSTAVOIDASFARASPOSSIBLELATENTISUNSTABLE，REDUCESOCCURSFROMVIOLENTPOSSIBILITYINTHECHANNELTHEPRESENTMORECOMMONLYUSEDENLARGEMENTCOMPONENTISTHEMMIC