1-8
IM AQ1200-01EN
Dead Zone
An area where the influence of a large event such as a connector’s connection point makes it
impossible to recognize other events that exist in that area is a dead zone. There are the following
two types of dead zones.
•
Event dead zone
An area where adjacent reflections cannot be separated. This is the area represented by the
pulse width between the two points on the waveform at the level that is 1.5 dB below the peak
value.
•
Attenuation dead zone
An area where, because there is a large reflection, the surrounding splice losses cannot be
measured.
Event dead zone
Attenuation dead zone
1.5 dB
Near-end Dead Zone Prevention
In sections where near-end reflection is detected, loss and reflections that occur at connections
cannot be detected. If you are measuring a short distance, connect a dummy fiber to move events
that are hidden in the near-end reflection the distance of the dummy fiber.
Do not bend the optical fiber.
AQ1200x
AQ1205x
Optical fiber being
measured
Dummy fiber
Event generation
point
Small reflection that was hidden
within a large reflection
Splice Loss
The AQ1200x/AQ1205x measures the distance and the loss between the specified points.
2 Point Markers
The AQ1200x/AQ1205x measures the distance and the loss between two points. If reflection is
detected between the two points, the return loss is also measured. The splice loss value changes
depending on the approximation method that you have specified. This can be used when Marker
Mode is set to Marker or Line.
Splice loss a (dB)
(Total loss)
(n when Marker Mode is set to Line)
(E when Marker Mode is set to Line)
2
1
d (km)
1.4 Waveform and Event Analysis
