Symmetricom XL-GPS - Manual (Page 76)

66 997-01530-01, Rev. C-25, Jan 2008
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1
Alarm Definitions
Clock Status
Locked: The XL-GPS clock is locked to the GPS reference source and is operating within the F73 Time
Error Threshold.
Unlocked: Check the other alarm indicators to determine the cause of the problem.
PLL
Locked: The clock PLL is locked and operating nominally.
Unlocked: The clock PLL is malfunctioning. Return to Symmetricom for service. See “H: Sales and
Customer Assistance” on page 143 .
GPS
Locked: The GPS receiver is receiving a sufficient number of valid GPS satellite signals and is
generating a valid timing solution.
Unlocked: The GPS receiver is not providing a valid timing solution due to one of the following causes:
• Insufficient visibility of GPS satellites at the antenna location.
• Poor GPS satellite signal strength
• A poorly positioned GPS antenna
• A broken or disconnected antenna cable
• An absent or non-functioning GPS receiver card
See “Installing the GPS Antenna” on page 13 for GPS antenna installation guidelines.
DAC
Locked: The DAC, which disciplines the clock oscillator to the reference source, is operating nominally.
Unlocked: The DAC is operating out of specifications. Return to Symmetricom for service. See “H: Sales
and Customer Assistance” on page 143 .
1st Time Lock
Time Error and Time Threshold
Time Error issues an alarm when the worst case time error ( “F13 – Time Error” on page 48 ) of the XL-
GPS system clock exceeds the user-set Time Threshold.
Note: With Time Threshold set to zero, the unit applies a default value of 150 nS.