User's Manual

Confidential&Proprietary105/122 SC‐DAS
The level of DOU’s Laser didoe is typically +1.5±1dBm. DOUs have various alarm such as LD Power
alarm,OverloadAlarmandPDalarms.
The level of Laser diode receivedfrom ROU/OEUis +7dBm±0.5dB.The level of Photo diode willbe
displayedwithlossesrelatedtothelengthofopticalcablesandinsertionlossofopticalconnectors.
Ingeneral,thelevelofopticalPDPOWERshouldbe+6dBmto+2dBm±1.5dB.
Furthermore,theODUhasthefunctionofautomaticallycompensatingforopticalcableloss.
Initially, if BIU communicates with the lower Unit(OEU,ROU), the optical loss compensation is
automaticallyaffected.
Duringopticalcompensation,theResultwindowshows"Processing"andthenaresultvalue.There
arethreetypesofresultsasfollows:
A. Success:Theopticalcompensationisnormallycompleted
B. OverOpticLoss:Generatedopticallossis5dBoormore.
C. CommunicationFail:CommunicationwithROUisinpoorconditin.
The ATT foroptical compensation can work based on the numerical expression of 12‐2*(LD
POWER‐PDPOWER).OpticalcompensationcanbemadenotonlyintheODUbutalsointheROU.
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6.2 ROUOverview
The figure below shows the SC‐DAS system link level (BIU‐ODU‐ROU). This section describes ROU‐
related information. The ROU receives various signals through optical modules. These signals are
filtered only for corresponding signal band from the MFR/ARF module and amplified with a High
Power Amplifier. Then, the multiplexer combines the signals with others and sends them to the
antennaport.
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Figure6.11–SC‐DASLinkbudgetforROU
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