Synchronization
• Time. A timeout set at initiation
• The value of the oscillator control signal
Locking to the optional reference:
• Non-failure status of the optional sync function
• Time. A timeout set at initiation
• The value of the oscillator control signal
The timeout is in both cases used to disqualify a locking attempt that
takes too long. A fault is sent to the BSC at timeout, but the internal
source will still try to lock to an available reference.
The function is terminated when synchronization is established.
18.3.6 FN offset
The FN (Frame Number) offset function makes it possible for a TRU at
a site to use a defined offset from the TDMA number distributed from
the central timing of the RBS. The offset value is added to the
distributed TDMA frame number.
The offset is configurable from the BSC per timeslot, provided that all
timeslots are disabled. Configuration of one timeslot will reconfigure all
the others. The configuration is carried out by the Functionality
Administration function.
18.4 Operational Conditions
18.4.1 Synchronizing to the Reference Source
Full synchronism is reached as noted below from function initiation.
Table 16 Synchronizing time
Cold start Transmission network as source 5 minutes
Optional frequency source 10 minutes
Warm start For both network and optional 90 s when there
are no jitters in
the synch.
source
18.4.2 Selection of Reference Source
The function handles one optional reference source or one PCM
reference source. The PCM reference must be marked available in order
to be considered for selection. The function handles that one or both
PCM interfaces are left unconnected.
There is no momentary change in phase or frequency of the RBS
caused by reselection of synchronization source.
18.4.3 Hold-over Operation
The "Hold-over entered time" is 5 minutes.
The "Hold-over expired time" is 60 minutes.
128 (306)
EN/LZT 123 2697 R5A
1998-08-13
© Ericsson Radio Systems AB
— All Rights Reserved —
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