User's Manual Part 3

Screen Service SDT 501 UB-C ARK 1-T Operations
May, 2010 v 1.0 Page 3 - 100
Alarm Description and limitations Troubleshooting
DVB-T 1PPS Lock
1PPS is not lock to the selected frequency reference. This
alarm’s RF OFF mask should always be enabled.
Alarm raising limitations:
The monitoring of this alarm is disabled when external 1 PPS
is not used (Heterodyne repeater modes) or when internal 1
PPS is selected (clock ref. set to internal) or when GPS clock
reference is selected and one of the GPS alarms (GPS
signal lock, GPS comm. alarm) is raised.
• If the frequency reference is Internal: internal PLL fault
• If the frequency reference is External:
o Internal PLL fault
o Lack of external 1PPS
o Hardware fault
• If the frequency reference is Internal:
o Check GPS alarms
o Internal PLL fault
o Hardware fault
DVB-T PPS Phase
1PPS is not lock to a common reference of the network. This
alarm’s RF OFF mask should always be enabled.
Alarm raising limitations:
The monitoring of this alarm is enabled only when the device
has SFN modulation enabled.
• Check 1PPS
• Hardware fault