ITU-T G.728 Annex I (05 1999) (英) Frame or packet

INTERNATIONALTELECOMMUNICATIONUNIONG.728TELECOMMUNICATIONSTANDARDIZATIONSECTOROFITUAnnexI(05/99)SERIESG:TRANSMISSIONSYSTEMSANDMEDIA,DIGITALSYSTEMSANDNETWORKSDigitaltransmissionsystems–Terminalequipments–CodingofanaloguesignalsbymethodsotherthanPCMCodingofspeechat16kbit/susinglow-delaycodeexcitedlinearpredictionAnnexI:FrameorpacketlossconcealmentfortheLD-CELPdecoderITU-TRecommendationG.728–AnnexI(PreviouslyCCITTRecommendation)ITU-TG-SERIESRECOMMENDATIONSTRANSMISSIONSYSTEMSANDMEDIA,DIGITALSYSTEMSANDNETWORKSForfurtherdetails,pleaserefertoITU-TListofRecommendations.INTERNATIONALTELEPHONECONNECTIONSANDCIRCUITSG.100–G.199INTERNATIONALANALOGUECARRIERSYSTEMGENERALCHARACTERISTICSCOMMONTOALLANALOGUECARRIER-TRANSMISSIONSYSTEMSG.200–G.299INDIVIDUALCHARACTERISTICSOFINTERNATIONALCARRIERTELEPHONESYSTEMSONMETALLICLINESG.300–G.399GENERALCHARACTERISTICSOFINTERNATIONALCARRIERTELEPHONESYSTEMSONRADIO-RELAYORSATELLITELINKSANDINTERCONNECTIONWITHMETALLICLINESG.400–G.449COORDINATIONOFRADIOTELEPHONYANDLINETELEPHONYG.450–G.499TESTINGEQUIPMENTSTRANSMISSIONMEDIACHARACTERISTICSG.600–G.699DIGITALTRANSMISSIONSYSTEMSTERMINALEQUIPMENTSG.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.999RecommendationG.728/AnnexI(05/99)iITU-TRECOMMENDATIONG.728CODINGOFSPEECHAT16kbit/sUSINGLOW-DELAYCODEEXCITEDLINEARPREDICTIONANNEXIFrameorpacketlossconcealmentfortheLD-CELPdecoderSummaryThisannexdefinesanextensionforrobustoperationoftheG.728algorithmat9.6,12.8and16kbit/sinthepresenceofframeerasureorpacketlossinmobileorpacketenvironments.SourceAnnexItoITU-TRecommendationG.728waspreparedbyITU-TStudyGroup16(1997-2000)andwasapprovedundertheWTSCResolutionNo.1procedureon27May1999.iiRecommendationG.728/AnnexI(05/99)FOREWORDITU(InternationalTelecommunicationUnion)istheUnitedNationsSpecializedAgencyinthefieldoftelecommunications.TheITUTelecommunicationStandardizationSector(ITU-T)isapermanentorganoftheITU.TheITU-Tisresponsibleforstudyingtechnical,operatingandtariffquestionsandissuingRecommendationsonthemwithaviewtostandardizingtelecommunicationsonaworldwidebasis.TheWorldTelecommunicationStandardizationConference(WTSC),whichmeetseveryfouryears,establishesthetopicsforstudybytheITU-TStudyGroupswhich,intheirturn,produceRecommendationsonthesetopics.TheapprovalofRecommendationsbytheMembersoftheITU-TiscoveredbytheprocedurelaiddowninWTSCResolutionNo.1.InsomeareasofinformationtechnologywhichfallwithinITU-T’spurview,thenecessarystandardsarepreparedonacollaborativebasiswithISOandIEC.NOTEInthisRecommendationthetermrecognizedoperatingagency(ROA)includesanyindividual,company,corporationorgovernmentalorganizationthatoperatesapubliccorrespondenceservice.ThetermsAdministration,ROAandpubliccorrespondencearedefinedintheConstitutionoftheITU(Geneva,1992).INTELLECTUALPROPERTYRIGHTSTheITUdrawsattentiontothepossibilitythatthepracticeorimplementationofthisRecommendationmayinvolvetheuseofaclaimedIntellectualPropertyRight.TheITUtakesnopositionconcerningtheevidence,validityorapplicabilityofclaimedIntellectualPropertyRights,whetherassertedbyITUmembersorothersoutsideoftheRecommendationdevelopmentprocess.AsofthedateofapprovalofthisRecommendation,theITUhadreceivednoticeofintellectualproperty,protectedbypatents,whichmayberequiredtoimplementthisRecommendation.However,implementorsarecautionedthatthismaynotrepresentthelatestinformationandarethereforestronglyurgedtoconsulttheTSBpatentdatabase.
ITU2000Allrightsreserved.Nopartofthispublicationmaybereproducedorutilizedinanyformorbyanymeans,electronicormechanical,includingphotocopyingandmicrofilm,withoutpermissioninwritingfromtheITU.RecommendationG.728/AnnexI(05/99)iiiCONTENTSPageAnnexI–FrameorpacketlossconcealmentfortheLD-CELPdecoder................................1I.1Scope...........................................................................................................................1I.2Normativereferences..................................................................................................1I.3Introduction.................................................................................................................1I.4Principlesofoperation................................................................................................2I.4.1Excitationextrapolation.................................................................................2I.4.2LPCfilter.......................................................