ITU-T G.997.1 Corrigendum 1 (12 2006) (英) Physical

InternationalTelecommunicationUnionITU-TG.997.1TELECOMMUNICATIONSTANDARDIZATIONSECTOROFITUCorrigendum1(12/2006)SERIESG:TRANSMISSIONSYSTEMSANDMEDIA,DIGITALSYSTEMSANDNETWORKSDigitalsectionsanddigitallinesystem–AccessnetworksPhysicallayermanagementfordigitalsubscriberline(DSL)transceiversCorrigendum1ITU-TRecommendationG.997.1(2006)–Corrigendum1ITU-TG-SERIESRECOMMENDATIONSTRANSMISSIONSYSTEMSANDMEDIA,DIGITALSYSTEMSANDNETWORKSINTERNATIONALTELEPHONECONNECTIONSANDCIRCUITSG.100–G.199GENERALCHARACTERISTICSCOMMONTOALLANALOGUECARRIER-TRANSMISSIONSYSTEMSG.200–G.299INDIVIDUALCHARACTERISTICSOFINTERNATIONALCARRIERTELEPHONESYSTEMSONMETALLICLINESG.300–G.399GENERALCHARACTERISTICSOFINTERNATIONALCARRIERTELEPHONESYSTEMSONRADIO-RELAYORSATELLITELINKSANDINTERCONNECTIONWITHMETALLICLINESG.400–G.449COORDINATIONOFRADIOTELEPHONYANDLINETELEPHONYG.450–G.499TRANSMISSIONMEDIACHARACTERISTICSG.600–G.699DIGITALTERMINALEQUIPMENTSG.700–G.799DIGITALNETWORKSG.800–G.899DIGITALSECTIONSANDDIGITALLINESYSTEMG.900–G.999GeneralG.900–G.909ParametersforopticalfibrecablesystemsG.910–G.919Digitalsectionsathierarchicalbitratesbasedonabitrateof2048kbit/sG.920–G.929Digitallinetransmissionsystemsoncableatnon-hierarchicalbitratesG.930–G.939DigitallinesystemsprovidedbyFDMtransmissionbearersG.940–G.949DigitallinesystemsG.950–G.959DigitalsectionanddigitaltransmissionsystemsforcustomeraccesstoISDNG.960–G.969OpticalfibresubmarinecablesystemsG.970–G.979OpticallinesystemsforlocalandaccessnetworksG.980–G.989AccessnetworksG.990–G.999QUALITYOFSERVICEANDPERFORMANCE–GENERICANDUSER-RELATEDASPECTSG.1000–G.1999TRANSMISSIONMEDIACHARACTERISTICSG.6000–G.6999DATAOVERTRANSPORT–GENERICASPECTSG.7000–G.7999PACKETOVERTRANSPORTASPECTSG.8000–G.8999ACCESSNETWORKSG.9000–G.9999Forfurtherdetails,pleaserefertothelistofITU-TRecommendations.ITU-TRec.G.997.1(2006)/Cor.1(12/2006)iITU-TRecommendationG.997.1Physicallayermanagementfordigitalsubscriberline(DSL)transceiversCorrigendum1SummaryThisCorrigendumcontains:–Clarificationtothemaximumnoisemarginparameter.–CorrectiontothereportingofSNRMODEovertheT-Sinterface.SourceCorrigendum1toITU-TRecommendationG.997.1(2006)wasapprovedon14December2006byITU-TStudyGroup15(2005-2008)undertheITU-TRecommendationA.8procedure.iiITU-TRec.G.997.1(2006)/Cor.1(12/2006)FOREWORDTheInternationalTelecommunicationUnion(ITU)istheUnitedNationsspecializedagencyinthefieldoftelecommunications.TheITUTelecommunicationStandardizationSector(ITU-T)isapermanentorganofITU.ITU-Tisresponsibleforstudyingtechnical,operatingandtariffquestionsandissuingRecommendationsonthemwithaviewtostandardizingtelecommunicationsonaworldwidebasis.TheWorldTelecommunicationStandardizationAssembly(WTSA),whichmeetseveryfouryears,establishesthetopicsforstudybytheITU-Tstudygroupswhich,inturn,produceRecommendationsonthesetopics.TheapprovalofITU-TRecommendationsiscoveredbytheprocedurelaiddowninWTSAResolution1.InsomeareasofinformationtechnologywhichfallwithinITU-T'spurview,thenecessarystandardsarepreparedonacollaborativebasiswithISOandIEC.NOTEInthisRecommendation,theexpressionAdministrationisusedforconcisenesstoindicatebothatelecommunicationadministrationandarecognizedoperatingagency.CompliancewiththisRecommendationisvoluntary.However,theRecommendationmaycontaincertainmandatoryprovisions(toensuree.g.interoperabilityorapplicability)andcompliancewiththeRecommendationisachievedwhenallofthesemandatoryprovisionsaremet.Thewordsshallorsomeotherobligatorylanguagesuchasmustandthenegativeequivalentsareusedtoexpressrequirements.TheuseofsuchwordsdoesnotsuggestthatcompliancewiththeRecommendationisrequiredofanyparty.INTELLECTUALPROPERTYRIGHTSITUdrawsattentiontothepossibilitythatthepracticeorimplementationofthisRecommendationmayinvolvetheuseofaclaimedIntellectualPropertyRight.ITUtakesnopositionconcerningtheevidence,validityorapplicabilityofclaimedIntellectualPropertyRights,whetherassertedbyITUmembersorothersoutsideoftheRecommendationdevelopmentprocess.AsofthedateofapprovalofthisRecommendation,ITUhadreceivednoticeofintellectualproperty,protectedbypatents,whichmayberequiredtoimplementthisRecommendation.However,implementersarecautionedthatthismaynotrepresentthelatestinformationandarethereforestronglyurgedtoconsulttheTSBpatentdatabaseat©ITU2007Allrightsreserved.Nopartofthispublicationmaybereproduced,byanymeanswhatsoever,withoutthepriorwrittenpermissionofITU.ITU-TRec.G.997.1(2006)/Cor.1(12/2006)iiiCONTENTSPage1)Correctiontothedefinitionofmaximumnoisemarginparameter..............................12)CorrecterrorinaccessofSNRMODEattheS/Tinterface..........................................1ITU-TRec.G.997.1(2006)/Cor.1(12/2006)1ITU-TRecommendationG.997.1Physicallayermanagementfordigitalsubscriberline(DSL)transceiversCorrigendum11)CorrectiontothedefinitionofmaximumnoisemarginparameterModify7.3.1.3.3and7.3.1.3.4asfollows:7.3.1.3.3DownstreamMaximumNoiseMargin(MAXSNRMds)ThisisthemaximumnoisemarginthexTU-Rreceivershalltrytosustain.IftheNoiseMarginisabovethislevel,thexTU-RshallrequestthexTU-CtoreducethexTU-Ctransmitpower