Sharp SD-AT1000W Spécifications télécharger pdf (Page 171)

Maxiva UAX

October 17, 2013

4‐7

888‐2693‐004 WARNING:Disconnectprimarypower priortoservicing.

Note

The table above provides only a rough estimate of the resulting power level. It does not take into account

any minor shifts in DRIVE due to compensating action in the LPU RF power control circuit.

4.3 LowPowerUnit(LPU)

Inadditiontothecontrolfunctionsdiscussedpreviously,theLPUalsoprovidesthemainexciterfunctionsforthe

UAXfamilyoftransmitters.Itconsistsofamodulatorsection(top2RUofLPU)andanamplifiersection(lower2RUof

LPU).TheLPUcanproduceupto100W(average)COFDMTVorATSCTVpower

,and150W(peakvisualwith10%

aural)analogTVpower.

TheLPUperf

ormsthefollowinggeneralfunctions:

• Inputsignalconditioningandswitching(inthecaseofredundantinputsignals)

• Channelencoding/modulation

• Linearandnonlinearpre‐correction

• UpconversiontothefinalRFchannel

• AmplificationtothefinalRFpowerlevel

TheLPUmodul

atorsectioncontainsuptosevencircuitboardsincluding:

• Signalproces sorboard.

• Precisefrequencyreferenceunitboard(PFRU).

• Up‐downconverterboard(UDC).

• Lowvoltagepowersupply(LVPS)board.

• Batterybackupboard.(option)

• TransmitterI/Ointerfaceboard.

• Analog,satellitereceiver,orASIoverIPinputboard(options)

4.3.1 LPUModulationOverview

Figure4‐5isanoverallblockdiagramoftheLPUmodulatorsection.Notethatthepowersupplyandbatterybackup

boardsha

venotbeenshownforthesakeofclarity.Thesewillbediscussedinasubsequentsection.

UAX16PA ‐0.6dB ‐0.6dB

UAX24PA ‐0.4dB‐0.4dB

UAX32PA ‐0.3dB‐0.3dB

Table4‐1PowerOutputwithSingleModuleRemoved

FailedModule

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Sharp SD-AT1000W Spécifications Page 171