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097-55501-01 Revision M – January 2009
TimeHub 5500 User’s Guide 187
Chapter 4 Testing and Configuring the TimeHub
Configuring CC Signals
– There is a non-zero CC delay enabled on the CC output being observed.
This is covered in the next topic, but the easiest thing to do is to
temporarily disable the CC delay so that alignment is expected to occur
without any timing offset. An alternative is to take into account the CC
delay value that has been programmed when observing the timing
relationships on the oscilloscope. For example, if a 3
s CC delay value
has been set (and is enabled), the alignment is successful when you can
observe a 3
s time difference between the CC input and CC output.
3. Once the phase alignment is as expected, disable the alignment process by
issuing the TL1 command
ED-EQPT:::SV277:::CCALIGN=N;
or clear the “Align CC Outputs to CC Input” button on the Configuration, Input
screen in TimeScan THC.
This causes the Master shelf to no longer use the CC IN 1 input as a reference,
returning to normal operation using either PRS or DS1 inputs. The Master shelf
maintains phase alignment and does not cause the output phase to shift suddenly.
Setting the Delay on CC Outputs
For both Master and Remote shelves, you can apply a timing offset to the CC
outputs to compensate for time delay associated with long cable runs. You set the
timing offset set in 80-nanosecond increments or in 100-foot increments using the
CCDENB and CBCOMP or CCDEL TL1 keywords, or you can set the timing offset
in 100-foot increments using TimeScan THC.
Each group of 20 ports on each output card group can have a unique delay value.
For example, you can assign a CC delay value to the first 20 ports of the “A” output
group, a different value to ports 21-40 of the “A” output group, a different value to
ports 1-20 of the “B” group, and so on.
Each individual output port can be selected to have the delay feature enabled or
disabled. For example, it is possible to delay ports 29 and 30 of a given card group
while not delaying any of the other ports in that group. You must enable the delay
function for a specific port in order for the delay to apply.
To set the CC delay values using TL1 commands, see
Using TimeScan THC
You set the CC delay parameters on the
Configuration
Output
tab in the
TimeScan THC application, as shown in
. You set the delay according to
the length of cable (in feet) connected to the output.