Specifications

A-3
Appendix A
Measurement Definitions
periodendswhentheerrorratioisbetterthan1x10
-3
for 10 consecutive seconds. These
10 seconds are considered part of the available time. % Unavailability is the ratio of the
unavailable seconds to the total gating period expressed as a percentage.
% Availability
The ratio of the available seconds to the total gating period expressed as a percentage.
% Errored Seconds
The ratio of the errored seconds in the available time to the total number of seconds in the
available time, expressed as a percentage.
% Severely Errored Seconds
The ratio of the total number of available seconds with an error ratio worse than 1 x 10
-3
to
the total number of available seconds, expressed as a percentage.
% Degraded Minutes
Severely errored seconds are discarded from the available time and the remaining seconds
are grouped into blocks of 60 seconds. Blocks which have an error ratio worse than
1x10
-6
are called Degraded Minutes and % Degraded Minutes is the ratio of the total
number of degraded minutes to the total number of 60 second blocks in the available time
expressed as a percentage. Incomplete blocks of less than 60 seconds are treated as
complete blocks of 60 seconds.
Power Loss Seconds
Displayed as the number of seconds the error detector is not able to make measurements
during a gating period owing to ac-power loss. The gating continues to the end of the
selected period following restoration of power.
Sync-loss Seconds
Displayed as the number of seconds the error detector loses pattern synchronization
during a gating period.
Error Location Analysis (Option UHJ instruments)
Error location is explained in Chapter 4, Operating Features and Specifications.