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Chapter 4 - Operation and Administration
4.11.2.2.1
Clock Mode
The Clock Mode parameters defines the location of the unit in the chain. The
available options are:
Master
Slave#1 (the first Slave unit in the chain, connected to the Master unit)
Slave#2 (the second Slave unit in the chain, connected to Slave#1)
Slave#3 (the third Slave unit in the chain, connected to Slave#2)
Slave#4 (the fourth Slave unit in the chain, connected to Slave#3)
The default is Master.
Under normal conditions, the clocks are supplied by the Master unit to the Slave
units. If Slave#1 will detect that it does not receive clocks for a certain period of
time, it will assume that the Master unit has failed and will start using its internal
10 MHz clock, supplying the clocks also to the other slave units (if exist). Slave#2
will wait for a longer period of time before assuming that both the Master and
Slave#1 have failed, and so on.
The functionality and operation mode of the main clocks is:
4.11.2.2.2
External 1PPS Clock (read-only)
The 1PPS (Pulse Per Second) clock is used to determine the air-frame start time.
Assuming that all systems use the same air-frame size and DL/UL Ratio, then,
when the 1PPS clock is received from a GPS system, this mechanism ensures
inter-site and intra-site synchronization among all sectors, preventing cross
interference and saturation problems. When using the internal 1PPS clock
(derived from the 10MHz clock source), only intra-site synchronization among
sectors can be achieved.
For a Master unit the default External 1PPS Clock is Disable (use internal 1PPS
clock source derived from either the built-in GPS receiver or from the 10MHz
clock).
For Slave units the default External 1PPS Clock is Enable (derived from the
previous unit in the chain).
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