EXFO FTB-1, User Manual

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Test Results
368
FTB-700G/800 Series
Performance Monitoring

UAS (Unavailable Second): Gives the count of the seconds
corresponding to the periods of unavailable time that begins at the
onset of 10 consecutive SES events, including these 10 seconds. A
period of available time shall begin at the onset of 10 consecutive
non-SES events, including these 10 seconds.

ESR (Errored Second Ratio) ( G.821 , G.826 , G.828 , and G.829 ): Gives
the ratio of the number of ES in available time (AS) during a fixed
measurement interval.
ESR = ES ÷ AS

SESR
(Severely Errored Second Ratio) (
G.821
,
G.826
,
G.828
, and
G.829 ): Gives the ratio of the number of SES in available time (AS)
during a fixed measurement interval.
SESR = SES ÷ AS

BBER
(Background Block Error Ratio) (
G.826
,
G.828
,
G.829
, and
M.2101 ): Gives the ratio of BBE in available time (AS) to total blocks in
available time during a fixed measurement interval. The count of total
blocks excludes all blocks during SESs.

DM (Degraded Minutes) ( G.821 only): A Degraded Minute is the
number of minutes in which the estimated error rate exceeds 10
-6
but
does not exceed 10
-3
. DM is determined by collecting all of the
Available Seconds, removing any SES grouping the result in 60-second
long groups and counting a 60-second long group as degraded if the
cumulative errors during the seconds present in the group exceed 10
-6
.