模拟电视发射系统改造实现数字电视地面广播的研究

上海交通大学硕士学位论文模拟电视发射系统改造实现数字电视地面广播的研究姓名：黄健申请学位级别：硕士专业：通信与信息系统指导教师：张文军20051201IIIIV10MHzATSCDVBGPSDELAYRAMVImplementationofDigitalTVTerrestrialBroadcastingbyReconstructingAnalogTVBroadcastingsystemAbstractComparewiththeanalogTV,digitalTVhastheadvantagesofhighqualityvideo,hightransmissionefficiencyandstronginterferenceresistance.WiththedevelopmentofdigitalTVterrestrialbroadcasting(DTTB),thelow-bitratemobileandhigh-bitratefixedreceptionsareavailable.AccordingtoChinesepresentanalogTVbroadcasting,peopleinthemostunderdevelopedareasstillhavetheproblemtowatchTV.DTTBcanbringgoodpicturesforsuchareasbyreplacingtheanalogTVtransmissionsystem.However,restrictedbytheeconomicalfactors,newDTTBtransmitterwillbringlargecosttosuchunderdevelopedarea.BasedontheexperimentswetransmittedsinglecarrierDTVbytheanalogtransmitter,thispaperpresentsahighefficiencyandlowcostreconstructionofanalogtransmissionsystemforDTTB.Thefullsolutioncontainsthestructuralreconstruction,highpoweramplifier(HPA)linearityandsinglefrequency(SFN)networkdesign.Wepresenttheanalogtransmitterstructuralreconstructionforeithersingleordualchanneltransmitterbycontinuingtouseitsmixerandhighpoweramplifier.Sincetheanalogtransmitterhasthelowerperformancethandigitaltransmitter,weanalysethetransmitsignalimpactedbytheHPAnonlineardistortionatlength.WiththecompareofthelinearizingVItechniques,weputforwardthebase-bandadaptivepre-distortertoimprovethelinearityoftransmitsignalandtheefficiencyofHPA.Aftertheanalogtransmitterstructuralreconstruction,theanalogTVcoveragemustbereconstructedtoDTTBsinglefrequencynetworkcoveragetomakegoodreceptionservice.Toimplementthedatatransportation,CY7B923/933producedbyCYPRESSisusedtotransmitandreceiveSFNdataviafiberandmicrowaveconnection.WeproposethenewschemeofdatatransportstructureforSFN,fromwhichthesystemclockand10MHzreferenceclockcanbeexactlyrecovered.BythedesignofDELAYRAM,thetransmitsignallatencyofeachtransmittercanbeconvenientlyadapted.InthecoverageofsingletransmitterandSFN,On-ChannelRepeater(OCR)isthehighefficientandlowcostmeantomeettheareawheresignalisblockedbythevariousobstacles.Inthisarticle,traditionalanalogOCRhasbeenstudied,andweproposeanimplementationofnewbasebanddigitalequalizedOCRforsinglecarriertransmissionsystem.ThedigitalequalizedOCRhasamuchbetterperformance,whichcanbewidelyusedinthecomplexrepeatenvironment,suchasurbanfilledwithhighbuildings.KEYWORDSDTV,DTTB,HPA,PRE-DISTORTER,SFN,OCRI    20061232006123II     2006123 11.11201-11-1Fig1-1AnalogTVBroadcastingSystemdiagram21.2[1]1-21-2Fig1-2DigitalTVBroadcastingSystemdiagramllll8MHz810lSFNl3llllDTTBCH39[2]DTTB1.3ATSC[3]DVB[4]ISDBDTTBATSC1997ITUATSCCOFDMDVB-T1998ITUATSC-8VSBTSRSTCMVSBATSCDVB-TTSIFFT2K8K4GIDVB-T2000Brazil[5]DVB-TATSC-8VSBISDB1.419992008201510DVB-CMPEG2/4TSDVB-C51.562.1NEC,RS2.2IOT[6]AB9040~50dB7080UHF7UHFIOTIOTABIOTIOTAB13.52.5815dB35dB20dB8dB8223050/2-1Table2-1ComparisonofAnalogTVTransmitter2.3[7]82.3.12-1Fig2-1DualChannelTVTransmitter2-1PIf38MHzVSBSIf31.5MHz2.3.22-2Fig2-2SingleChannelTVTransmitter92-22.42.4.12-3Fig2-3DualAnalogTransmitterStructuralReconstruction2-3MPEG2/4TSMPEG2/410101[8]10kW1kW2.4.22-4Fig2-4SingleAnalogTransmitterStructuralReconstruction2-42.51120DVB-TATSC2.6123.1lkW3.2[9]vfsfafABCa=2tvfpsb=2tfpc=2tafpiU=Acosa+Bcosb+Ccosc(3.1)lk2k3k130li2i3iU=kU+kU+kU(3.2)(3.1)(3.2)O122222223333333U=k(Acosa+Bcosb+Ccosc)+k{0.5(A+B+C)+0.5(Acos2a+Bcos2b+Ccos2c)+[ABcos(ab)+ACcos(ac)+BCcos(bc)]}+k{0.25(Acos3a+Bcos3b+Ccos3c)+0.75(Acosa+Bcosb+Ccosc)+1.±±±2222222222225ABCcos(abc)+0.75[ABcos(2ab)+ACcos(2a4-c)+BAcos(2ba)+BCcos(2bc)+CAcos(2ca)+CBcos(2cb)]+1.5(ABcosa+ACcosa+BAcosb+BCcosb+CAcosc+CBcosc)}±±±±±±±3.33.2.11011.3161.7323230.75kBCcos(2b-c)(vf+2.36)31.5kABCcos(abc)-+(vf+207)230.75kBC31.5kABCAB31.5kABC230.75kBCvf+207vf+2.36vf+207143.2.2DGDPDGDP3.3DGDP231.5kBAcosb2AABDG231.5kBAcosb1kBcosbDP3.2.31MHz330.75kAcosa153.33.3.1[10]AM/AMAM/PM3-13-23-1AM/AM3-2AM/PMFig3-1AmplitudeDistortionCurveFig3-2PhaseDistortionCurve2[11]AM/AM3-1AM/PM163-20x(t)=2(t)cos[t+(t)]swq3.4HPA0z(t)=2G[(t)]cos{t+(t)+[u(t)]}swqy3.50w(t)s(t)qG[(t)]s[u(t)]yHPA3.5pq00z(t)=2G[(t)]cos{t+(t)}-2G[(t)]sin{t+(t)}swqswq3.6InphaseNonlinearityPhaseshift090QuadratureNonlinearityInputOutput3-3Fig3-3QuadratureModulationNonlinearityModelofNonlinearDistortionHPA3-3AM/AMAM/PMIQpG[]=G[]cos[]ssys3.7qG[]=G[]sin[]ssys3.8AM/PMqG[]s0HPAAM/PMqG[]sQAM/PM173.3.2AM/AM3-4AM/PM3-5-5-4-3-2-1012345-4-3-2-101234IchannelQchannel-5-4-3-2-1012345-5-4-3-2-1012345IchannelQchannel3-416QAM3-516QAMFig3-416QAMAmplitudeDistortionFig3-516QAMPhaseDistortion373-6706MHz50dBHPA3-7HPA35dB3-63-7Fig3-6UpconverterOutputSpectrumFig3-7HPACouplingSpectrumTabooChannel183-83-93713dB3722dB373-83-9Fig3-8ACIBetweenAnalogandDigitalChannelFig3-9ACIBetweenDigitalChannelsATSCDVB[12]3.4193.5204.1/[13]4.21dB1dB1dBP1dB4-16-10dB1dB1dB2dB214-1Fig4-1HPAInputvs.OutputCurve-50dBc4.3[14]12224.4THPA4.4.1[15]4-2()aVt()mVt()dVt()23()mVt()dVt()aVt212,FF4-2Fig4-2RFPre-distorterDiagram4.4.23Xx-_ry