Specifications

Section-3 Operation
October 17, 2013
3‐84
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Figure 3-78 LPU ATSC Status Screen 3
TAD
Transmittertoante
nnadelay.Thisthethroughputdelay,measuredafterthesignalleavesthe
exciternetworkdelaycircuitandtravelstotheoutputofthetransmitter.Thisdelayisimportantif
thenetworkconsistsoftransmittersfromdifferentmanufactures,wheretheoutputprocesstime
willchangefromonemanufacturertoanother.
TotalDelay
Thisisthere
sultanttotaldelaybeingmanagedbythetimingrequirementstomeettheemission
time,includingTAD.
#ofDlyInc
Numberofde
layincrementsthatthemodulatorhashadtoperformtomaintainemissiontiming.
Highorcontinualincrementingnumbershereindicateinstabilityinthenetwork'sdistributionof
thetransportstreamortiming.Ideallythisiszero.
#ofDlyDec
Numberofdelaydecrementsthatthemodulatorhashadtoperformtomaintainemissiontiming.
Highorcontinualincrementingnumbershereindicateinstabilityinthenetwork'sdistributionof
thetransportstreamortiming.Ideallythisiszero.
Table3‐75XmtrHome>ExciterHome>Status>ATSCModulator(screen1)
Field Explanation
NetworkID
ThisistheNe
tworkIDenteredatthedistributedtransmissionadapter.IntheUSA,iscustomarytouse
theassignedTSIDforthestationasthenetworkID.
LockMetho
d
ATSC'sA/
110standardspecifiedtwomethodstoachievetimingreferenceforSFNemission,theyare
GPSandstreamlocked.
Inthest
reamlockedmode,theexciterextractsit'stimingfromthe19.39MHzclockembeddedinthe
transportstream.
Theexc
itersectiononlysupportsGPSlockedmode.Thismodeissetbythedistributedtransmission
adapter.Ifanothermanufacturer'sadapterisbeingusedandithasbeensetupforstreamlockedmode,
theLPUwillnotlockandafaultwillbeindicated.
WatermarkSerial
Da
taInhibited
RFWa
termarkisaslowspeedserialdatastreamthatcanbemodulatedontoeachofthe8symbol
levelsemitted.Thisenablesuseofspecializedtestequipmentinthefieldtofigureoutwhich
transmittersarebeingreceivedinanSFNenvironment.
Inad
ditiontotransmitteridentification,theRFWatermarkcanbeusedasaslow‐speedserial
communicationchannel.TheLPUdoesnotcurrentlysupportthischannel,buttheDTxAhastheability,
incompliancewiththestandard,totelladownstreammodulatortoinhibitthemodulationofthisdata
onthewat
ermarkornot.ThisisareadbackofthesettingofthatbitintheDT xP.
Table3‐74XmtrHome>ExciterHome>Status>ATSCModulator(screen2)
Field Explanation