Computer Hardware Installation Guide

Functional description 913
Table 373
System clock specification and characteristics
Specifications CCITT
EIA
Base Frequency 20.48 MHz 20.48 MHz
Accuracy
±3 ppm ±1 ppm
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
Since the accuracy requirements for CCITT and EIA Stratum 3ND are so
different, it is necessary to have two TCVCXO which feature different values
of frequency tuning sensitivity.
Table 374
System clock specification and characteristics
Specifications CCITT
EIA
Base Frequency 20.48 MHz 20.48 MHz
Accuracy
±3 ppm ±1 ppm
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
Since the accuracy requirements for CCITT and EIA Stratum 3 are different,
it is necessary to have two TCVCXOs which feature different values of
frequency tuning sensitivity.
Table 375
System clock specification and characteristics
Specifications CCITT
EIA
Base Frequency 20.48 MHz 20.48 MHz
Accuracy
±3 ppm ±1 ppm
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
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 01.04 Standard
Release 5.0 23 May 2008
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