2-6
IM AQ7280-01EN
Distance Range
Set the distance range according to the length of the optical fiber cable. The distance range that you
can select varies depending on the wavelength. Specify a distance range value that is greater than
the length of the optical fiber cable that you will measure. If you specify a shorter value, the AQ7280
will not be able to perform measurements properly. The longer the distance that you specify, the
more time measurements will take. When you specify the distance range, the optimum pulse width
and attenuation values are set automatically.
Cable Length
Distance Range
Notes
Unknown
Auto
0 m to 160 m
200 m
160 m to 400 m
500 m
400 m to 800 m
1 km
800 m to 1.6 km
2 km
1.6 km to 4 km
5 km
4 km to 8 km
10 km
8 km to 16 km
20 km
16 km to 24 km
30 km
24 km to 40 km
50 km
40 km to 80 km
100 km
80 km to 160 km
200 km
160 km to 240 km
300 km
240 km to 320 km
400 km
Cannot be specified for wavelengths 850 nm or 1300 nm
320 km to 400 km
512 km
Cannot be specified for wavelengths 850 nm or 1300 nm
Pulse Width
The pulse width has the following characteristics.
• A short pulse width enables you to measure with a high resolution, but you cannot measure long
distances.
• A long pulse width enables you to measure long distances, but you cannot measure with a high
resolution. Also, dead zones are larger with long pulse widths.
The pulse widths that you can select vary depending on the distance range, as shown in the
following table.
Distance Range
Selectable Pulse Widths
200 m
3 ns, 10 ns, 20 ns, 30 ns, 50 ns, 100 ns, 200 ns, 300 ns, 500 ns
500 m
3 ns, 10 ns, 20 ns, 30 ns, 50 ns, 100 ns, 200 ns, 300 ns, 500 ns
1 km
3 ns, 10 ns, 20 ns, 30 ns, 50 ns, 100 ns, 200 ns, 300 ns, 500 ns, 1 µs
2 km
3 ns, 10 ns, 20 ns, 30 ns, 50 ns, 100 ns, 200 ns, 300 ns, 500 ns, 1 µs
5 km
3 ns, 10 ns, 20 ns, 30 ns, 50 ns, 100 ns, 200 ns, 300 ns, 500 ns, 1 µs
10 km
3 ns, 10 ns, 20 ns, 30 ns, 50 ns, 100 ns, 200 ns, 300 ns, 500 ns, 1 µs
20 km, 30 km
10 ns, 20 ns, 30 ns, 50 ns, 100 ns, 200 ns, 300 ns, 500 ns, 1 µs, 2 µs
50 km, 100 km
20 ns, 30 ns, 50 ns, 100 ns, 200 ns, 300 ns, 500 ns, 1 µs, 2 µs, 5 µs, 10 µs, 20 µs
200 km
30 ns, 50 ns, 100 ns, 200 ns, 300 ns, 500 ns, 1 µs, 2 µs, 5 µs, 10 µs, 20 µs
300 km or more
50 ns, 100 ns, 200 ns, 300 ns, 500 ns, 1 µs, 2 µs, 5 µs, 10 µs, 20 µs
High SNR Mode
If the optical fiber cable to be measured is connected to a passive optical network (PON) system,
because an optical splitter for splitting the optical fiber cable is installed in the system, you will not
be able to measure optical pulses that are reflected from a position further away than the optical
splitter using normal measurement. This feature enables you to correctly measure optical pulses
that are reflected from positions such as this.
OFF: Optical pulses excluding those from PON systems can be measured.
ON: PON system optical pulses can be measured.
Note
• High SNR mode can be turned on when the pulse width is set in the range of 50 nm to 1 μm.
• This cannot be used when the wavelength is 850 nm or 1300 nm.
2.1 Setting the Measurement and Analysis Conditions
