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1、AbstractAbstractDMRdigitaltrunkingcommunicationstandardisrecentlyproposedbythe
EuropeanTelecommunicationsStandardsInstitute,comparedwithtraditionalanalog
systemsandotherdigitalsystems,DMRsystemhasthecharacteristicsofhighspectral
efficiency,advancedcontrolfeaturesandexcellentaudioperformance,itcana
2、lsobe
backwardscompatiblewiththetheanalogtrunkingcommunicationsystem,thereforeit
hasbeenwidelyusedinpublicserviceintheindustry.TheresearchanddevelopmentofDMRterminaltendstobematureathomeand
abroad,buttherealwayshavesomequestionsasfollows:First,theintegrationofDMR
dedicatedchipisnotsohighthattheexi
3、stingmainstreamdevelopmentplatformisstill
inaccordancewiththeprotocolhierarchicaldesignwhichhaslowresourceutilization.
Then,theDMRphysicallayeruses4CPMmodulationmethod,yetthestudybasedon
4CPMbasebandsignalprocessingtechniquesisrelativelyless.Forthisveryreason,
studyingthekeytechnologyofDMRphysical
4、layeranddesigningitsdigitalinterphone
prototypehashighpracticalandusingvalue.ThisthesisfocusesontheDMRtrunkingcommunicationstandard,referringtoits
technicalcharacteristicsandairinterfaceprotocol,studiesthekeytechnologiesof
physicallayerinDMRdirect-modemachines.Firstly,designingandsimulatingthebase
5、bandalgorithmsinDMRphysicallayer.
TheDMRuses4CPMmodulationmethod,andwedesignthebasebandsimulation
modelinDMRphysicallayerwhichbasesontheperformanceandrelization.ThePLL
demodulationmethodreachesabiterrorperformanceoflessthan10-3in12dBEb/N0,
whichmeetstheDMRvoicecommunicationrequirements.Secondly,th
6、eoveralldesignofphysicallayerdigitalfrond-endisgiven.Weuse
FPGAtorealizethephysicalbasebandalgorithms,designthedigitalsignalprocessing
modulesandinterfacemodulesdetailedly.Throughfunctionalsimulationandtiming
simulation,weensurethattheworkflowofDMRphysicallayerinDMRmachinesis
correct.Thirdly,verif
7、yingtheperformanceofphysicallayerdesigninDMRterminal.We
builtaboard-levelverificationonthehardwareplatform,throughFPGAonline
debuggingtools,DAC,ADC,DSPandRFinterfacemoduletestandalgorithm
processingmoduletestareb