Nortel Networks Circuit Card 311 - Manual (Page 898)

898 NTAK10 2.0 Mb DTI card
The NTAK10 2MB DTI clock controller functions and features include:
• phase-locking to a reference, generating the 10.24 Mhz system clock,
and distributing it to the CPU through the backplane. Up to two
references at a time may be accepted.
• providing primary to secondary switchover and auto-recovery
• preventing chatter
• providing error burst detection and correction, holdover, and free running
capabilities
• complying with 2.0Mb CCITT specifications.
• communicating with software.
• providing jitter filtering.
• making use of an algorithm to aid in detecting crystal aging and to
qualify clocking information.
The NTAK10 2MB DTI clock controller functions and features include:
• phase-locking to a reference, generating the 10.24 Mhz system clock,
and distributing it to the CPU through the backplane. Up to two
references at a time can be accepted.
• providing primary to secondary switchover and auto-recovery
• preventing chatter
• providing error burst detection and correction, holdover, and free running
capabilities
• complying with 2.0 Mb CCITT specifications
• communicating with software
• filtering jitter
• making use of an algorithm to aid in detecting crystal aging and to
qualify clocking information
Reference switchover
Switchover may occur in the case of reference degradation or reference
failure. 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 said to be out of specification. If the reference being used 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 01.04 Standard
Release 5.0 23 May 2008
Copyright © 2003-2008, Nortel Networks
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