Nortel Networks 1000 - Manual (Page 814)

814 NTAK20 Clock Controller daughterboard
Table 340
System clock specification and characteristics (cont’d.)
Specifications CCITT EIA
Operating Temperature 0 to 70 C ±1 ppm 0 to 70 C ±1 ppm
Drift Rate (Aging) ±1 ppm per year ±4 ppm in 20 years
±60 ppm min. ±10 ppm min. Tuning Range (minimum)
±90 ppm max. ±15 ppm max.
Input Voltage Range 0 to 10 volts, 5V center 0 to 10 volts, 5V center
EIA/CCITT compliance
The clock controller complies with 1.5 Mb EIA Stratum 3ND, 2.0 Mb CCITT
or 2.56 Mb basic rate. The differences between these requirements mainly
affect PLL pull in range. Stratum 4 conforms to international markets (2.0
Mb) while Stratum 3 conforms to North American markets (1.5 Mb).
The clock controller complies with 1.5 Mb EIA Stratum 3ND, 2.0 Mb CCITT
or 2.56 basic rate. The differences between these requirements mainly
affect PLL pull in range. Stratum 4 conforms to international markets
(2.0Mb) while stratum 3 conforms to North American market. (1.5 Mb).
The clock controller complies with 1.5 Mb EIA Stratum 3ND, 2.0 Mb CCITT
or 2.56 Mb basic rate. The differences between these requirements mainly
affect PLL pull in range. Stratum 4 conforms to international markets (2.0
Mb) while Stratum 3 conforms to North American markets (1.5 Mb).
Monitoring references
The primary and secondary synchronization references are continuously
monitored in order to provide autorecovery.
The primary and secondary synchronization references are continuously
monitored in order to provide autorecovery.
The primary and secondary synchronization references are continuously
monitored in order to provide autorecovery.
Reference switchover
Switchover occurs in the case of reference degradation or loss of signal.
When performance of the reference degrades to a point where the system
clock is no longer allowed to follow the timing signal, then the reference is
out of specification. If the reference is out of specification and the other
reference is still within specification, an automatic switchover is initiated
without software intervention. If both references are out of specification,
the clock controller provides holdover.
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 02.06 Standard
27 August 2008
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