Ericsson Radio Systems AB PKRC1311004-1 Manual De Usuario
Synchronization
the lack of reference source. This fault actually implies for an ITU-T
G.703 2048 kbit/s system that the reference on both PCM-A and PCM-
B is not usable. If the RBS has not regained its synchronization either
by re-establishment or reselection within 60 minutes (when TF mode is
master and stand-alone) and within 15 minutes (when TF mode is
slave), it is reported to the BSC which orders the RBS to disable all
radio transmission. This maximum time for the internal oscillator to
guarantee synchronization quality is known as "Hold-over expired
time". The function is terminated when the reference source is
considered as usable or after "Hold-over expired time".
G.703 2048 kbit/s system that the reference on both PCM-A and PCM-
B is not usable. If the RBS has not regained its synchronization either
by re-establishment or reselection within 60 minutes (when TF mode is
master and stand-alone) and within 15 minutes (when TF mode is
slave), it is reported to the BSC which orders the RBS to disable all
radio transmission. This maximum time for the internal oscillator to
guarantee synchronization quality is known as "Hold-over expired
time". The function is terminated when the reference source is
considered as usable or after "Hold-over expired time".
31.6
Supervision of Reference Source
Purpose
The function should decide if the reference source is to be considered
as usable or not. This is done by supervision of the synchronization
source as well as the quality of the synchronization signal.
as usable or not. This is done by supervision of the synchronization
source as well as the quality of the synchronization signal.
Precondition and Initiation
The function is initiated when synchronization to the reference source is
established.
established.
Description
Depending on if the PCM interface or the Optional reference source or
another RBS is used as a reference, the following criteria are used for
evaluation of the reference source.
another RBS is used as a reference, the following criteria are used for
evaluation of the reference source.
PCM interface as reference:
•
LOS (Loss Of Signal), LOF (Loss Of Frame alignment) or AIS
(Alarm Indication Signal) detected by physical interface.
(Alarm Indication Signal) detected by physical interface.
•
Illegal high jitter and wander characteristics. The limit is specified
in /G.823/.
in /G.823/.
•
Illegal high relative frequency deviation. The limit is 0.1 ppm.
Optional reference source:
•
Failure of the optional reference source.
•
Illegal high jitter and wander characteristics. The limit is specified
in /G.823/.
in /G.823/.
•
Illegal high relative frequency deviation. The limit is 0.1 ppm.
Other RBS as reference:
•
Interruption.
•
Correct and continuous frame number.
•
Illegal high wander characteristics. The limit is specified in /
G.823/.
G.823/.
•
Illegal high relative frequency deviation. The limit is 0.1 ppm.
252 (421)
EN/LZT 720 0008
R1A
2001-06-26
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