Ericsson Radio Systems AB PKRC1311004-1 Manual De Usuario
Synchronization
Table 120
TF Config. Parameters
Selected Synch. Source Type
TF Mode
TF Synch.
Source Type
Source Type
Optional Synch.
HW
HW
No Optional
Synch. HW
Synch. HW
Not defined
Not defined
Optional
PCM
Master/
Stand-alone
Stand-alone
Not defined
Optional
PCM
PCM
PCM
PCM
Internal
Optional
PCM
1)
Slave
Does not care
Other RBS
Other RBS
1)
Rejected by the Capability Conformance Check function.
If the transport network is used for synchronization, the executive
reference is taken from PCM interface A at start-up of the RBS on
condition that interface A is available for synchronization and is fault
free. Otherwise PCM interface B is selected if it is available and fault
free.
reference is taken from PCM interface A at start-up of the RBS on
condition that interface A is available for synchronization and is fault
free. Otherwise PCM interface B is selected if it is available and fault
free.
The executive reference may change from one of the PCM interfaces to
the other when signal on the executive reference is lost (AIS, LOF or
LOS condition on the selected executive reference, see function
Supervision of Reference Source), provided that a signal is detected at
the other interface and that the other reference is marked "available".
the other when signal on the executive reference is lost (AIS, LOF or
LOS condition on the selected executive reference, see function
Supervision of Reference Source), provided that a signal is detected at
the other interface and that the other reference is marked "available".
The function is terminated when a new executive reference source has
been selected or if the executive PCM reference regains its
synchronization signal before a reselection is attempted or if a
reselection is made to another synchronization source. There is no
momentary change in phase or frequency of the RBS caused by
reselection of synchronization source.
been selected or if the executive PCM reference regains its
synchronization signal before a reselection is attempted or if a
reselection is made to another synchronization source. There is no
momentary change in phase or frequency of the RBS caused by
reselection of synchronization source.
31.5
Hold-Over Operation
Purpose
If the reference signal is considered not to be usable, the RBS cannot
use its values for regulation of the internal oscillator. The Hold-over
operation function keeps the RBS synchronized for a period of time
even though the reference signal is not present.
use its values for regulation of the internal oscillator. The Hold-over
operation function keeps the RBS synchronized for a period of time
even though the reference signal is not present.
Precondition and Initiation
The function is initiated when the reference signal is not usable.
Description
The function when initiated freezes the control panel parameters for the
internal oscillator at the present value, meaning that the oscillator
frequency is kept constant except for ageing and temperature drift. The
RBS will still be considered as synchronized and the supervision of the
reference source will continue. After 5 minutes lack of reference signal
known as "Hold-over entered time" a fault is sent to the BSC reporting
internal oscillator at the present value, meaning that the oscillator
frequency is kept constant except for ageing and temperature drift. The
RBS will still be considered as synchronized and the supervision of the
reference source will continue. After 5 minutes lack of reference signal
known as "Hold-over entered time" a fault is sent to the BSC reporting
EN/LZT 720 0008
R1A
2001-06-26
251 (421)
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