Specifications

Section-5 Maintenance
November 11, 2013
5‐12
Copyright©2013,HarrisBroadcast
WARNING:Disconnectprimarypowerpriortoservicing. 888‐2628‐300
5.9 AnalogPowerCalibrations
Otherthansystemforward&reflectedcalibrationsduringinstallation,powercalibrationshouldberequiredonlyif
thedownconverterboard,theRFdetectorboard(inTCU),orifadirectionalcouplerorsignalcableis replaced.
However,calibrationissimpleandcanbedonewheneveritisdeemednecessary.Theonly
requiredpower
calibrationsare:
a. SystemForwardPower(afterfilters)
b. SystemForwardSound(aural)Power
c. PACabinetForwardPower(beforefilters)
d. PACabinetForwardSound(aural)Power
e. SystemReflectedPower(afterfilters)
f. PACabinetReflectedPower(beforefilters)
g. ExciterForwardPower
h. PDUForwardPower
Note
Forward and reflected power calibrations should only be done while operating the transmitter into a
known good load or a low VSWR antenna system.
5.9.1 AverageandPeakPowerConversion
Withablankinglevel(blackpicturewithnosetup)signalappliedtothetransmittervideoinputterminalsandsync
levelsetto300mV(PAL)or40IRE(N TSC),therequiredaveragecarrierpowercanbecalculatedbymultiplyingthe
requiredpeakpowerofthetransmitterbyone ofthefactors
below,dependingonsystemtype.
Thechartbelowliststhesupportedsystems,theconversionfactorforvisiononlycalibration,andconversionfactors
forcalculatingaveragepowerwhenauralcarrierispresentinthesignal.
Alsolistedaretheformulastocalculatefactorsforotherauralinjectionlevels,aswellastheformulaforcalculating
thefactorwhenthereismorethan1auralcarrier,suchasNicamorDualCarriersoundsystems.
Table5‐3AveragetoPeakConversionFactors
Analog
System
Visual
Only
Visualplus(MONO)AuralInjectionatIndicatedLevels
‐8dB ‐9dB ‐10dB ‐11dB ‐12dB ‐13dB ‐14dB ‐15dB
B 0.567 0.726 0.693 0.667 0.647 0.630 0.617 0.607 0.599
G 0.567 0.726 0.693 0.667 0.647 0.630 0.617 0.607 0.599
H 0.595 0.753 0.721 0.695 0.674 0.658 0.645 0.634 0.626
I 0.609 0.767 0.735 0.709 0.688 0.672 0.659 0.648 0.640
D 0.595 0.753 0.721 0.695 0.674 0.658 0.645 0.634 0.626
K 0.595 0.753 0.721 0.695 0.674 0.658 0.645 0.634 0.626
K1 0.595 0.753 0.721 0.695 0.674 0.658 0.645 0.634 0.626
M 0.595 0.753 0.721 0.695 0.674 0.658 0.645 0.635 0.626
N 0.597 0.755 0.723 0.697 0.676 0.660 0.647 0.636 0.628