Specifications

Section-5 Maintenance
October 17, 2013
5‐22
Copyright©2013,HarrisBroadcast
WARNING:Disconnectprimarypower priortoservicing. 888‐2693‐004
5.6.1.1 AverageandPeakConversionFormulaeandExamples
AveragePower=PeakVisualPower*Factor
PeakVi
sualPower=AveragePower/Factor
Example1:Ca
lculatetheaveragepowerofaSystemMtransmitteroperatingat1000Wpeakvisualwithanaural
injectionlevelof‐10dB.
Factorfo
rSystemMwith‐10dBauralinjection=0.695
AveragePo
wer=1000W*0.695=695W
Example2:CalculatethepeakvisualpowerofaSystemKtransmitterwith‐13
dBauralinjectioniftheaveragepower
is1600W.
Factorfo
rSystemKwith‐13dBauralinjection=0.645
PeakVi
sualPower=1600W/0.645=2480W
Example3:Ca
lculatetheaveragepowerofaSystemBtransmitteroperatingat60kWpeakvisualwithnoaural.
FactorofSyste
mB,visualonly=0.567
AveragePo
wer=60kW*0.567=34.02kW
Usethef
ollowingformulatocalculatefactorsforotherauralinjectionlevels:
Factor=v+10
(a/10)
Where:v=visualonlyfactorforsystem
a=auralinjectionlevel
*Incas
eswithmultipleauralcarriers,(Nicam,DualCarrier)addthefactorsforeachauralcarriertothevisualfactor.
Example4:Aur
alcarriersat‐13dBand‐20dBforsystemB
Factor=v+10
(a/10)+10(a/10)
Factor= v+10
(‐13/10)+10(‐20/10)
Factor= 0.56
7+0.0501+0.01
Factor=0.62
7
5.6.2 AnalogForwardCalibration
Forwardpoweriscalibrate dat10dBbelowmodelpowerandatmodelpowertoensuregoodmeteringlinearity
overthefull10%‐100%range.Theforwardpowerreferencesample istypicallytakenfromadirectionalcoupler
beforethemaskfilterinthesystemandregulatesthepowerofthetransmitteroutputbef
oreanyfilterlosses.
Thesy
stemforwardpowersampleistakenfromaforwardportonthepre‐filterdirectionalcoupler(showninFigure
5‐11).Thecou
pledportwillhaveanattenuatorpadandassociatedcabling(andalsoatwo‐waysplitterifusedina
dualLP
Uconfiguration).TheintendedoperatingconfigurationhastheFWDsamplepadselectedsothatatfull
systemoutputthesample(s)attheLPUFWDinput(seeFigure5‐12)wil
lbeapproximately0dBmafterfactoringin
couplerva
lue,cablingloss,splitterloss(ifinstalled),andpadvalue.