Specifications

Maxiva UAX
October 17, 2013
5‐19
888‐2693‐004 WARNING:Disconnectprimarypower priortoservicing.
Copyright©2013,HarrisBroadcast
5.6 AnalogPowerCalibrations
Analogpowercalibrationdiffersfromdigitalpowercalibration.Usethefollowinginformationwhencalibratinga
transmitteroperatinginanalogmode(NTSC/PAL/SECAMtelevision).
Equipmentnee
ded:
• HPEPM‐seriesPowerMeterand8482HPowerSensor,orAgilentE4418BandType“N”toSMAadapter(or
equivalent).MetershouldbecapableofdisplayingmeasuredvaluesinWattsorindBm.
• Precisiondi rectional couplers(precisionmeaningthecouplingratioshavebeenaccuratelymeasuredforthe
operatingfrequencies).
• Videosignalsource.TektronixTG700orequivalent.
• Blackpicturewithzerosetup
• TektronixVM700Tmeasurementsystemorequivalent
• Spectrumanalyzer(tomeasureintermodulationproducts).HP8150orequivalentwithanalogmode.
TheUA
Xtransmitterhasbeencalibratedatthefactory .Fieldcalibrationcanbeperformedanytimeitisneeded.
PowercalibrationshouldberequiredonlyifaUDC(updownconverterinLPU),PAB,LPU,directionalcoupler,or
samplecableisreplaced.
Caution
POWER CALIBRATIONS SHOULD ONLY BE DONE WHILE OPERATING THE
TRANSMITTER INTO A KNOWN GOOD LOAD SUCH AS A STATION TEST
LOAD. BE CERTAIN THAT THE LOAD IS A CONFIRMED 50 OHMS AND HAS
THE CAPABILITY TO HANDLE THE POWER THAT WILL BE GENERATED BY
THE TRANSMITTER.
Forwardcalibrationmustbeperformedfirstandisfollowedbyreflectedcalibration.Afterselectingthecalibration
type,presstheStartCalsoftkeytobeginthecalibrationprocess(seeFigure5‐10onrigh
tbelow).
Figure 5-10 System Calibration options
System Calibration started
Powerc
alibrationsinclude:
• Forward‐Powerattheoutputofthetransmitteramplifyingstages,beforethebandpassfilter(BPF).
• Reflected‐Poweratthe outputofthetransmitteramplifyingstagesandbeforethebandpassfilter(BPF).
• UDCOut‐PoweratoutputofLPUmodulatorstage(SMAconnectoronupperrearofLPU)
• LPUForward‐Powerattheoutput(typeN)oftheLPUamplifiersection
• PAB#Forward‐Powerattheoutputofindividualpoweramplifierblocks
• PAB#Reflected‐Powerattheoutputofindividualpoweramplifierblocks