Irig; Aux Ref - Symmetricom XLi User Manual

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The GPS Primary Receiver indicator corresponds to the GPS receiver configured as "Primary" in F119.
The GPS Secondary Receiver indicator corresponds to the GPS receiver configured as "Secondary" in
F119.
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The GPS Receiver indicators report "OK" if the corresponding GPS receiver card is configured as "Dis-
abled" in F119 or if the card is physically removed from the XLi.
With good conditions and excellent visibility of the sky, the GPS receiver should track multiple GPS sat-
ellites on a continuous basis—faults from the GPS Receiver should be very infrequent and short in dura-
tion. Under more difficult conditions and with poorer visibility of the sky, faults will be more frequent and
last longer, but they should still be intermittent—coming and going as GPS satellites come in and out of
view. As long as the Clock Status doesn't alarm, these brief GPS faults will have little effect on the XLi
clock and corresponding outputs. The person operating the XLi should characterize the frequency and
duration of faults for a given installation, and should investigate and take action if the pattern of faults
changes significantly or doesn't meet requirements.
When the indicator reports a fault, use F60 to check the number of visible satellites and F119 to check if
the GPS antenna cable is showing an "open" or "short" condition. Check that the GPS antenna installa-
tion conforms to the guidelines given in the GPS Antenna installation section. Check the antenna,
antenna cable, and connections for problems.
Note:
Note: When using the GPS receiver with an antenna splitter, an antenna fault may occur due to a
DC block in the antenna path. The antenna fault can be avoided by using a splitter that provides
a load resistor to simulate the antenna current draw.
If a GPS receiver reports a continuous fault, and the GPS antenna and antenna cable have been tested
and found to be good, contact Symmetricom Global Customer Assistance.

IRIG

Status: OK or Fault
The IRIG indicator reports "OK" when an IRIG input on J1 is providing valid time. It reports a "Fault" if
one of the following is true:
• The time code signal isn't connected to J1 on the main CPU card.
• F110 isn't configured correctly for a given time code format or impedance configuration.
• There is a high signal-to-noise ratio in the AM code.
• The DC level shift code level is inadequate or has too much jitter.
To solve a fault from the IRIG indicator, check that the preceding items are configured/set up correctly.
Depending on how F74 is configured, the user may need to take additional steps to control which refer-
ence the XLi uses. See the F74 function reference section in this user guide.

Aux Ref

Status: OK or Fault
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XLi Time & Frequency System
XLi-man, Issue 8, 6/17/2008, Rev. H
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