Specifications

Maxiva ULX Series
November 11, 2013
4‐3
888‐2628‐300 WARNING:Disconnectprimarypowerpriortoservicing.
Copyright©2013,HarrisBroadcast
TheTCUinthemaincabinetcontainsaPCM(processorcontrolmodule)whichactsasthetransmitterinterface.
However,adepopulatedTCUispresentineachaddedPAcabinet.TheMCMcardmonitorsthepowersamplefrom
itscabinetandissuesthepropervoltagetothepredriverstomaintainthecabinet
powerregulation.ThisALCloop
residesineachcabinet.ThereisnoSystemALCLoop.
Inadditiontoprovidingmaincabinetpowerregulation,themainTCUalsoissuesthecabinetpowerreference.This
referenceisusedbytheALCloopineachcabinettoraiseorlowerthetransmitterpowerascommandedbytheend
user.ThissignalissentviaCANmessages.
Figure4‐2onpage4‐3illustratesthepowercontrolfunctionality.Ifthe
mainTCUisdown,theadditionalPAcabinetsmaintaintheircurrentpoweroutput.
Ineachcabinet,thecabinetpowerreferenceiscomparedtothedetectedcabinetRFpowersampleandthe
resultanterrorvoltage(cabinet#ALC)isproduced.Theerrorvoltageisusedtocontrolthepredrivergain,which
determinesthecabinetoutput power.
ThelocalTCUpowerraiseandlowerbuttonsprovidesameansofindividualcabinetpowercontrolwiththeALC
enabled.Thisprovidesameansofsettingandcalibratingtheindividualcabinetoutputpowertoensurecorrect
cabinetcombininginamultiplecabinetsystem.
TheTCUineachcabinethaspowercontrolAUTOandmanualbuttons.ThesebuttonsturncabinetALConandoff.If
theALCisdisabled,thecabinetpowercanberaisedorloweredviathelocalTCUpowerraiseandlowerbuttons.
Thisisanopenloopmodeandisintended
primarily asacabinettestmode(cabinetoperatedindependentlyofthe
mainTCU).
TheTCUsamplesthecabinetforwardpowertentimespersecond.It’smainroleistomaintaincabinetpower
regulationtocompensateforthermaldriftintheamplifiers.
Figure 4-2 Control System Simplified Block Diagram

MAIN UCP
System Power Referenc
e
From System Bus
S
÷
16 PAs
Cabinet 1 ALC
S
÷
16 PAs
Cabinet 2 ALC
S
÷
16 PAs
Cabinet 3 ALC
PA CAB
UCP
PA CAB
UCP
CABINET
COMBINER
Transmitter Power
Sample
(Used for power
Monitoring only. Not
used for ALC)
(Used for power raise/lower
command. Not used for ALC)
Transmitter Power Sample
From M CM
Cabinet Bus
From MCM
Cabinet Bus
From M CM
Cabinet Bus
Main TCU
PA Cab TCU
PA Cab TCU
Cabinet Combiner