5-32
U
SER
M
ANUAL
750000992/16
Using an OTDR module
MTS
e
Both End Measurement
The Both End measurement function allows the results of measurements made in
both directions of the fiber (Origin to End or End to Origin) to be used to obtain
more accurate splice and connector loss results.
Measurement Principles
The Both End measurement function uses the Trace Overlay function "Overlay
trace function" on page 5-28.
The traces obtained form the two measurements (one in each direction) are
displayed with event markers. They are first displayed superimposed, then one
of them is inverted (left
↔
right), in order that the markers associated to the same
events are on the same horizontal position (see "Both End Measurement display"
on page 5-34).
The Both End measurement result table show the following loss types:
•
The O -> E and E -> O
*
losses correspond to the measurements made in each
direction. They are different because the insertion loss and reflectance
thresholds of the segments situated at either side of the event are different.
•
The last loss is equal to half the sum of the two previous losses. By thus
taking the average value of both previous results we eliminate the error due
to the difference of the reflectance thresholds from either side of the event.
Therefore this loss corresponds to the real value of the insertion loss of the
event.
•
The loss displayed in the last line of the table represents the total loss of the
analysed link.
It is possible to define a splice loss threshold beyond which the result is
displayed in red in the table. This threshold can be selected in the OTDR TEST
SET menu, on the
Splice Alarm Th.
line, (see "Selecting measurement result
display parameters for both end measurement" on page 5-5).
Execution of a Both End measurement
Display of two traces O to E and E to O saved in memory
In this case, before loading these traces, you have to check that:
•
the two traces have not the same direction (E->O and O->E); if necessary
change the direction in the
Memory Info
menu, on the line
Direction
from the
FILE
page.
•
measurement results are available for both traces.
To load the traces, from the
FILE
page:
1.
Select the required file and display it by successively pressing the <Load>
and <Trace> keys.
2.
Select the other file required and successively press the <Load> and
<Overlay> keys to superimpose it over the previously displayed trace.
*. O=origin, E=End
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
