Appendix
D Clock Modes
Installation and Operation Manual
D-6
DSL and PSN Timing Modes
ACE-3105, ACE-3205 Ver. 5.2
forwarded by ACE-3105, ACE-3205 to the BTS and Node B over Ethernet or N x
E1/T1 interfaces, as shown below.
Figure
D-3. Adaptive Clock Recovery
Adaptive clock recovery is supported over SHDSL or ADSL2+ interfaces, yet it
requires dedicated clock recovery hardware and software license.
NTR Clock Recovery
In NTR clock recovery, the DSLAM receives the clock stream via its BITS interface,
and then forwards it via the DSL line as an NTR clock stream towards ACE-3105,
ACE-3205. The DSLAM receives the clock stream from either:
•
A GPS system
•
An SDH connection
•
A clock recovery gateway (such as ACE, located near the DSLAM).
Figure
D-4. NTR Clock Recovery
NTR clock recovery is supported over SHDSL only. NTR has higher frequency
accuracy than adaptive clock recovery.
Timing over PSN
In the application illustrated below, the master clock is retrieved by ACE-3105 and
ACE-3105, ACE-3205 from the packet-switched network, using a dedicated clock
Note
