12778474-002-2 Revision F – March 2004
TSG-3800 User’s Guide
91
Operating the TSG-3800
Setting Up Input Reference Controls
Phase history can provide a general indication of whether or not clocks are
following the input reference.
Comparing phase history with clock control value history to isolate clock and
input alarms.
Phase data continuously ascending and descending indicates frequency offset.
Phase data oscillation up and down indicates excessive network wander.
The display readings are in nanoseconds (chronological).
To display the most recent phase measurements for all inputs, type:
PHASE
then press
Enter
For more information, refer to
Phase Command
, on page 353.
Provisioning MTIE and Frequency Alarms
The TSG-3800 measures the Frequency offset and Maximum Time Interval Error
(MTIE) between each input and the clock in use. MTIE limits are expressed in 10
-9
s
or nanoseconds. Frequency limits are expressed in 10
-12
s/s or
picoseconds/second. When an input exceeds a user-specified threshold, the
instrument responds in a user-defined manner.
The operator can specify two fault threshold limits (designated as L1 and L2) and
fault modes (Fail, Alarm, Report, and Ignore) for MTIE and frequency offsets. This
allows one threshold to serve as an early warning of failure and the second to serve
as a failure indicator. You can specify different fault thresholds and limits to each
input port. There are three pre-defined L1 and L2 fault threshold limits for MTIE and
Frequency: PRS, OCN, and MCD (see
Input Command
, on page 350).
Table 3-2
shows the pre-defined MTIE settings for PRS, OCN, and MCD and
Table 3-3
shows
the pre-defined Frequency settings for PRS, OCN, and MCD.
Table 3-2. MTIE Pre-defined Settings
Configuration
Time Scale
Limit 1 (Fail)
Limit 2 (Alarm)
PRS
T100
270
216
T1000
540
432
T10000
1080
864
OCN
(Factory Default Setting)
T100
324
270
T1000
648
540
T10000
1296
1080
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