ITU-T G.728 Amendment 1 (05 2006) (英) Revised Anne

InternationalTelecommunicationUnionITU-TG.728TELECOMMUNICATIONSTANDARDIZATIONSECTOROFITUAmendment1(05/2006)SERIESG:TRANSMISSIONSYSTEMSANDMEDIA,DIGITALSYSTEMSANDNETWORKSDigitalterminalequipments–CodingofanaloguesignalsbymethodsotherthanPCMCodingofspeechat16kbit/susinglow-delaycodeexcitedlinearpredictionAmendment1:RevisedAnnexJ–Variablebit-rateoperationofLD-CELPmainlyforvoiceband-dataapplicationsinDCMEITU-TRecommendationG.728(1992)–Amendment1ITU-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.799GeneralG.700–G.709CodingofanaloguesignalsbypulsecodemodulationG.710–G.719CodingofanaloguesignalsbymethodsotherthanPCMG.720–G.729PrincipalcharacteristicsofprimarymultiplexequipmentG.730–G.739PrincipalcharacteristicsofsecondordermultiplexequipmentG.740–G.749PrincipalcharacteristicsofhigherordermultiplexequipmentG.750–G.759PrincipalcharacteristicsoftranscoderanddigitalmultiplicationequipmentG.760–G.769Operations,administrationandmaintenancefeaturesoftransmissionequipmentG.770–G.779PrincipalcharacteristicsofmultiplexingequipmentforthesynchronousdigitalhierarchyG.780–G.789OtherterminalequipmentG.790–G.799DIGITALNETWORKSG.800–G.899DIGITALSECTIONSANDDIGITALLINESYSTEMG.900–G.999QUALITYOFSERVICEANDPERFORMANCE–GENERICANDUSER-RELATEDASPECTSG.1000–G.1999TRANSMISSIONMEDIACHARACTERISTICSG.6000–G.6999DATAOVERTRANSPORT–GENERICASPECTSG.7000–G.7999ETHERNETOVERTRANSPORTASPECTSG.8000–G.8999ACCESSNETWORKSG.9000–G.9999Forfurtherdetails,pleaserefertothelistofITU-TRecommendations.ITU-TRec.G.728(1992)/Amd.1(05/2006)iITU-TRecommendationG.728Codingofspeechat16kbit/susinglow-delaycodeexcitedlinearpredictionAmendment1RevisedAnnexJ–Variablebit-rateoperationofLD-CELPmainlyforvoiceband-dataapplicationsinDCMESummaryAnnexJtoITU-TRec.G.728definesa40kbit/sextensionoptimizedforvoicebanddatasignalsoftheexistingAnnexG/G.728–16kbit/sfixedpointspecification.ThemaindifferencebetweenthecodecdescribedherebyandthecodecdescribedinAnnexG/G.728istheapplicationofaTrellis-CodedQuantization(TCQ)approachtocodebooksearch.TheTCQapproachreplacestheanalysis-by-synthesisapproachtocodebooksearchofITU-TRec.G.728onlyinvoicebanddata(VBD)mode.ThebackwardadaptationofthepredictorachievedinVBDmodeisalmostidenticaltothebackwardadaptationachievedinspeechmode(ITU-TRec.G.728).Additionally,thesameadaptationcycleisusedforbothspeechmode(ITU-TRec.G.728)andVBDmode.Inspeechmode,the40kbit/srevertstotheLD-CELPofITU-TRec.G.728.ThisannexincludesanelectronicattachmentcontainingtestvectorsforimplementationverificationofAnnexJ/G.728.Amendment1providescorrectionstoinconsistenciesidentifiedinthedescriptionofthegaincompensationmoduleofAnnexJ/G.728.Thesechangesdonotaffecttheexistingtestvectors.SourceAmendment1toITU-TRecommendationG.728(1992)wasapprovedon29May2006byITU-TStudyGroup16(2005-2008)undertheITU-TRecommendationA.8procedure.iiITU-TRec.G.728(1992)/Amd.1(05/2006)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.Asof