Larus 80-100-400 Issue 1, July 2006
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A-1
tarClock 200E AA versus AB Architecture
1.
t track and hold assembly. A
track and hold assembly is one of the following:
One 54511/54512/54513 Input Card plus:
•
522 Stratum 3E/LNC Track and Hold Clock Card (AA or AB)
•
4591 GPS Stratum 1/PRC Track and Stratum 3E/LNC Hold Clock Card
•
523 Stratum 2/TNC Track and Hold Clock Card (AA or AB)
•
4593 GPS Stratum 1/PRC Track and Stratum 2/TNC Hold Clock Card
(AB)
Appendix A
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S
A redundant StarClock 200E system contains two inpu
single
One 54
--OR--
One 5
(AB)
--OR--
One 54
--OR--
One 5
NOTE:
In a system that includes the Model 54550 Information Management Card, the 54550 and
track and hold card versions must support the same input architecture, AA or AB.
There are one to ten output driver cards in the system. Output cards 54571, 54572,
54573, 54574, 54575, and 54577 are capable of switching between timing reference
signals from DS1/E1/2048 KHz/CC/5 MHz/10MHz Input 1 and Input 2, Track and Hold
A, and Track and Hold B. The first track and hold assembly to power up and produce
timing pulses will be the initial active timing source for the
2.
output driver cards, so all
these output cards will utilize the same reference signal.
.
Assuming there is no operator intervention:
he
first valid input signal that becomes available after the holdover mode is entered.
ld card goes into holdover mode and
switches to track the secondary input signal.
3
Systems with AA architecture (refer to Figure A-1) have both input track and hold
assemblies tracking the same input, either Input 1 or Input 2. If there is a failure of the
tracked input, both assemblies go into holdover mode and search between Input 1 and
Input 2 for a good input signal. Each assembly will independently acquire and track t
Systems with AB architecture (Figure A-2) have each input track and hold assembly
tracking a different default input signal, i.e., Input Track and Hold A tracking Input 1
signal, Input Track and Hold B tracking Input 2 signal, or vice versa. If there is a failure
of the primary input, the active track and ho
Whichever the architecture, the system is nonrevertive. For example, in a system with
AB architecture, Input Track and Hold A is tracking DS1/E1/2048 KHz/CC 5 MHz/10