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CXR Larus 80-100-400 Issue 1, July 2006 1-13
1.43
Each system may also use performance monitor and alarm reporting cards,
comprised of one or two 54541 or 54542 Synchronization Monitor Cards, the
54560 Alarm Interface Card, and the 54550 Information Management Card. In
general, alarms are reported by front panel light emitting diode (LED)
indicators, by relay contact closures on the 54560 card, and by alarm
messages from the 54550 card to an OSS or local craft terminal.
NOTE:
An input jack is provided on the front panel of the 54541/54542 card. The
bantam size (-20 dBdsx signal level) permits the fifth DS1/E1 input signal to be
received via front panel access.
1.431 The 54580 Network Time Server (NTS) Card, available as an option with the
GPS system, distributes time for precise synchronization of client computer
clocks over a packet network. It is fully documented separately in CXR Larus
user manual 80-100-286 issue 2.
1.44
The CXR Larus StarClock 200E offers a fully redundant wander- and jitter-free
source of framed ones, composite clock, or square waves synchronized to a
suitable framed DS1 or E1 reference, 5 or 10 MHz reference, or GPS atomic
time reference. Jitter and wander attenuation is a standard function of the track
and hold cards. The StarClock 200E system provides inputs for two DS1/E1
references, two 5/10 MHz references, and two GPS antenna connections.
1.45
The average bit rate of the DS1 input references must be in the range of 1.544
Mbps ±7.1 bps for Stratum 3E or 1.544 Mbps ±0.04 bps for Stratum 2
oscillators to "pull-in" and track. E1 input signals must be in the range of 2.048
Mbps ±9.4 bps (LNC) or 2.048 Mbps ±0.05 bps (TNC).
1.46
For redundant Stratum 3E/LNC and Stratum 2/TNC systems, two digitally
controlled frequency synthesizers (one in each 54522 or 54523 card) track the
separate DS1/E1 framed input reference signals while the inputs are within the
above frequency limits. For Stratum 1/PRC systems, the digitally controlled
frequency synthesizers are adjusted to compensate for drift relative to the GPS
atomic time.
1.47
The frequency synthesizers initially operate in the acquire mode, attempting to
adjust their frequency to bring the phase error relative to the reference input to
zero. When the phase error is relatively small, the frequency synthesizers shift
into the tracking mode.
