IDEAL INDUSTRIES FIBERTEK, Руководство пользователя, Страница: 104 / 147

Chapter 6
Fiber Optics Diagnostics (TRACETEK)
TRACETEK displays its measurement data in a graphical format similar to that of an
ODTR, with the X-axis representing the distance from the handset and the Y-axis
displaying the relative reflection (Return Loss) of each event. TRACETEK instantly
displays the overall length to the end of the fiber and allows the operator to scroll a
cursor to find the distance to any event on the screen. This functionality allows the
operator to quickly measure overall fiber length, locate breaks in the fiber, locate
individual reflective events, and check the relative reflection of events to identify
defective connections.
The TRACETEK display provides a “roadmap” of the fiber at a glance. The number at
the bottom of the screen, marker 5, indicates the measured distance to the end of the
fiber. As with an OTDR, TRACETEK does not require a piece of equipment or a person
at the opposite end of the fiber under test. For this reason, TRACETEK cannot
differentiate between the expected end of the fiber or a break in the cable. If there is
a break in the cable this reading will tell you how far down to look for the break.
¾
Marker 1 indicates the first connector attached to your launch jumper.
¾ Marker 2 indicates the two connectors in the middle of the fiber under test. The
height of the reflected pulse (called a Fresnel) indicates the relative reflection of
each event. In the High-Resolution mode, a good connector should not go much
above the halfway point on the display. In this example, the two connectors
should be cleaned, and the first appears to be a bit worse than the second.
¾ Marker 3 is at the end of fiber. This reflection is expected to be quite large since
it is at the end of the cable and represents a glass-to-air interface.
Markers 1 and 6 indicate the user-moveable cursor and its position respectively. The
cursor can be move by three methods: in very fine steps using the left and right arrow
keys on the keypad, in medium size steps using the
and soft-keys, or
in large steps by holding the SHIFT button while pressing the LEFT/RIGHT ARROW
keys on the keypad.
In the figure above, the display shows a trace of the same fiber as before, but the two
connectors in the middle were cleaned using the IDEAL Starter Cleaning Kit included
with your TRACETEK module. It is clearly evident that a dirty connector, even one that
appears clean to the naked eye, can cause significant return loss problems in the link.
After being cleaned, both connectors are well below half scale and should present no
problems with network operation.
Cleaning connectors with any fiber-optic system is of utmost importance. Whenever
there is any doubt about a test result, the first action is to clean the suspect
connectors and retest the link.
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