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1、有线电视基础知识和技术（BasicknowledgeandtechnologyofCATV）BasicknowledgeandtechnologyofcableTV.Txtwoman:remembertoeat,havefun,sleepwellanddrinkwell.Onceexhausted,andotherwomenspendourmoney,liveinourroom,sleepourhusband,soakourboyfriend,butalsobeatourbaby.Basicknowledgeandtechnolo
2、gyofCATVSubjectiveevaluationofCATVimagequalityThesubjectiveevaluationoftheclient'simagequalityisbasedonthefiveleveldamagestandard,whichshouldbecarriedoutaccordingtotheinternationalstandardofGB74014.2,five,andthe4stageimageisthedesignstandardoftheCATVsystem.FortheChine
3、seTVstandardC/N=N+6.4dB,theimagelevel4(S/N=36.6dB)correspondstoC/N=43dB.CATVbidirectionalsystemfrequencydivisionconfigurationTypicalspectrumarrangementsareproposedCommoncablerelatedcharacteristicsTechnicalcharacteristicsandparametersofcommoncable(20C)Structuralcharact
4、eristicsofcommoncableNote:theabove-5,-7,-9and-12arephysicalfoamingcablesThefrequencycharacteristicofcoaxialcableis:TheleveloflossL-cableinafrequencypoint,K-coefficient(-12,k=0.3;k=-9,0.38-0.4;-7,k=0.5-0.55),F-signalfrequencyForthesamekindofcable,thefollowingapproximat
5、erelationship:Bythisrelation,theattenuationvaluesofeachfrequencypointnotlistedinthetablecanbeapproximatelyobtained.Theminimumbendingradiusofcableshouldbegreaterthan10timesofthecablediameter,temperaturecoefficientreductiontimeis2perthousandcable,cableloopDCresistancete
6、mperaturecoefficientis4.Theabovelistisatroomtemperature(20DEGC)andtheresistancevalueofcableattenuation,attenuationofTCincabletemperatureandresistancecalculationformulaisasfollows:Lattenuation=L(20degrees)*[1+2perthousand*(T-20DEGC)]Rresistance=R(20degrees)*[1+4perthou
7、sand*(T-20DEGC)]Basicdataofopticalfibercabledesign1single-modefiberloss1310nm=0.35dB/(includedinourknowledgefusionjointlossafter0.4dB/ofourknowledge)1550nm=0.22dB/(includedinourknowledgefusionjointlossafter0.25dB/ofourknowledge)2,opticalconnectorloss0.5dB/(connectormo
8、delisSC/APCorFC/APC)3.Opticalsplitterinsertionloss:L=10lglambda%(lambda-to-spectralratio)4.OpticalshuntunitadditionallossThe
