Symmetricom ATS-6511A User Manual page 92

Note: These settings are only used in the legacy and two_way_disabled fiber_modes.
Fiber Delay Difference (fiber_delay_diff):
Description: When there is a fiber path difference between the transmit and receive paths
of either input channel from the ATS 6501 to the ATS 6511, the difference must be
determined and set in the ATS 6511 when using two way mode. This is normally the case
when non-duplex fibers are used or non-duplex patch panels are used in the path. The
difference can be measured using the ATS 6511 in legacy mode and measuring the two
paths for the channel using a portable clock and time interval counter. Each value must
specify the fiber delay from the ATS 6511 to the ATS 6501 minus the fiber delay from the
ATS 6501 to the ATS 6511. Contact Symmetricom if you need help with setting up a
system which has differences in fiber lengths for a channel.
The formula to calculate these values are:
fiber_delay_diff=((6511 to 6501 Fiber A Delay) - (6501 to 6511 Fiber A Delay)) or ((6511
to 6501 Fiber B Delay) - (6501 to 6511 Fiber B Delay))
The example below shows a difference on Fiber Pair A of 13nSec and Fiber Pair B of -
21nSec.
Syntax: fiber_delay_diff [Fiber A Diff (nt)] [Fiber B Diff (nt)]
Command Example:
ATS-6511>fiber_delay_diff_ 1.3E-8 -2.1E-8
Query:
ATS-6511>settings fiber:delay_diff
[channelA] 1.300000000000000e-08
[channelB] -2.100000000000000e-08
Fiber Mode:
Description: Sets the mode of operation for the ATS 6511 phase steering algorithm. The
phase steering algorithm uses the fiber input signals to steer out the phase offset of the ATS
6511.
legacy: (Prior to 5.X.X) Used on systems that do not require two way over fiber
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and are using the 4372A plug in module. Refer to the software release notes for
information on delay difference that may be created when upgrading software.
two_way: Used for systems that need two way over fiber operation to
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automatically compensate for fiber delays in the system. The ATS 6511 will use its
own phase measurement along with a phase measurement it receives from the
upstream 4372A-T to remove the phase offset between the ATS 6501 and itself.
two_way_disabled: For use in systems that cannot use two way over fiber mode
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but are using a 4372A-T. The fiber delay for each path can be determined and set in
the same manner as when setting the fiber delay.
ATS-6511A/B/C Users Guide
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DOC 6511_Release K