Symmetricom SSU-2000 User Manual page 189

Note: If the SSU-2000 is configured with Clock module firmware
(14113015-000-5) Revision H.00 or later, then you must DISABLE the
input's PBO functionality using ICS, TL1, or SNMP commands. The
PBO functionality has been moved into the Clock module and is not
under software control. If you do not disable the SSU-2000's Input
PBO setting, it will conflict with the PBO function in the Clock module.
Frequency Alarms
The Input module measures the phase difference over time of an input signal and
calculates the input frequency. The frequency calculation has a frequency
measurement resolution of 2.5E
The module monitors the ongoing Frequency calculations and logs an alarm if the
frequency calculation exceeds either of the two user-settable alarm masks.
Frequency readings that violate either mask at any point cause an alarm at a
user-set severity level. Refer to
information on setting alarm levels.
Although Frequency is continuously calculated against both clocks, frequency
alarms are logged only if the measurements against the currently selected clock
violate one of the frequency alarm masks.
MTIE Calculation
Maximum Time Interval Error (MTIE) is a measurement of the relative noisiness of
an input signal. The Input module automatically (without user intervention)
calculates MTIE for its inputs in accordance with the specifications in ANSI T1.101
and ITU 812 and generates reports on demand for a 24-hour period.
MTIE data is retrieved on hour boundaries, though the stop time used can be
current time. Reported time periods include 0.05, 0.1, 10.0, 100.0, 1000.0, 10000.0,
and 100000.0 seconds.
MTIE Alarms
The Input module monitors the ongoing MTIE calculations and logs an alarm if the
MTIE calculation for any of several window sizes exceeds user-set masks.
The Input module software maintains two alarm masks, each with thresholds at 10,
100, 1000, 10000, and 100000 seconds. MTIE readings which violate either mask
at any point cause an alarm at a user-set level. Refer to
on page 114 for more information on setting alarm levels.
Although MTIE is continuously calculated against both clocks, MTIE alarms are
logged only if the measurements against the currently selected clock violate one of
the MTIE alarm masks.
12713020-002-2 Revision F.01 – January 2007
-12
.
Changing Factory Defaults, on page 114 for more
Chapter 7 Input Module Reference Data
Japanese Sine Wave Input Module
Changing Factory Defaults,
SSU-2000 User's Guide 189