Specifications

Section-3 Operation
October 17, 2013
3‐44
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Figure 3-42 LPU ISDB-T Setup Screen 2
Table3‐31XmtrHome>ExciterHome>Setup>ISDB‐TModulator>Next(screen2)
Fields Explanation
SFNMode Choicesar
eMFN(MultipleFrequencyNetwork)orSFN(SingleFrequencyNetwork).
EqpmntID
Rangeis0to63.E
quipmentIDisassignedbytheSFNnetworkadministratorandisprovidedto
allowauniqueidentifierforeachtransmitterintheSFNcell.WhentheequipmentIDintheIIP
packetmatchesthelocalequipmentID,thentheIIPTimeOffsetinformationisextracted
RFO
utputifSFN/IIPError
Choicesar
eYesorNo.Ifnoisselected,transmitterwillbemutedifSFNinformationismissing
fromthetransportstreamorSFNdelaycalculationsresultinnegativedelaysordelaysgr eater
thanonesecond.Ifyesisselected,theexciterwilloutputRFwhichisnotproperlySFN
synchroniz ed.
LocalOffsetDelay
Thisallowsthetransmitteroperatortosetadelayforthetransmitterlocally.Itspurposeisto
causetheRFoutputtobedelayedadditionallybytheamountentered.
LocalRFDela
y
Thisisthetimedelaycau
sedbythetransmitter’shighpowerfilterandtransmissionlineas
welltheGPSdelaycausedbyitscablelength.ItspurposeistocausetheRFoutputtobe
releasedearlierbytheamountenteredtherebynullingouttheabovementionedRFdelays.
IIPRe
newalFlagCntr
(counter)
RenewalFlagisabitintheIIPpa
cketwhich,onthetransitionfrom1to0,indicatesthe
informationintheIIPpacketisvalid.
There
newalflagcounterprovidestheoperatorwithanindicationthattheIIPinformationis
beingupdatedonaregularbases.NotethattheMaxDelayandIIPTimeOffsetisonlyupdated
whentheIIPRenewalFlagchangesfrom1to0.Onexciterpowerup,themodulatorwillwait
fo
ranIIPrenewalflagtransitionfrom1to0,whichindicatestheIIPpacketdataisvalid.
IIPTi
meOffset
TheII
PTimeOffset,inms,allowstheSFNAdapterupstreamtosendanoffsettimeto
individualtransmittersintheSFNnetwork.ThisallowstheSFNnetworkoperatortochange
anyofthetransmitterdelaysintheSFNfromonecentrallocation,theSFNadapter.
IIPMa
xDelay
Thisdela
yissentfromtheSFNAdaptortothemodulator.Itindicatesthetimefromthetime
stampintheIIPpackettowhentheheadofthemultiplexedframeistobeemitted.
ProcessingDela
y
ProcessingDel
ay,inms,isthetimerequiredforthesignaltopropagatethruthemodulator
duringthemodulationprocess.Thistimeomitsthedelaycausedbythetimeinterleaver.
NetworkDel
ay
ThistimeinmsisthetimerequiredforthetransportstreamtotravelfromwheretheIIP
packetistimestampedintheSFNadaptoruntilthepacketisreceivedbythemodulator.
SFNSt
orageTime
Storageti
me,inmsistheMaxDelayplusthelocalRFDelay,minustheprocessingDelay,minus
theLocalOffsetDelay,minustheIIPOffset
Delay,mi
nustheNetworkDelay.SFNStorageTimeisthedelaybufferincorporatedinthe
modulatortoprovidetherequireddelayforSFNoperation.