3-7
IM AQ1200-01EN
Optical Pulse Measurement and
Analysis Conditions
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Index
App
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
500 m
3 ns, 10 ns, 20 ns, 50 ns, 100 ns, 200 ns, 500 ns
1 km
3 ns, 10 ns, 20 ns, 50 ns, 100 ns, 200 ns, 500 ns, 1
μ
s
2 km
3 ns, 10 ns, 20 ns, 50 ns, 100 ns, 200 ns, 500 ns, 1
μ
s
5 km
3 ns, 10 ns, 20 ns, 50 ns, 100 ns, 200 ns, 500 ns, 1
μ
s
10 km or 20 km
3 ns, 10 ns, 20 ns, 50 ns, 100 ns, 200 ns, 500 ns, 1
μ
s
50 km or greater
3 ns, 10 ns, 20 ns, 50 ns, 100 ns, 200 ns, 500 ns, 1
μ
s, 2
μ
, 5
μ
s, 10
μ
s
• When the distance range is set automatically, you cannot select the pulse width.
• When you specify the pulse width, the attenuation is automatically set to the optimum value.
Attenuation
If large reflections are caused by optical connectors or by breaks in the optical fiber, the waveform may
be saturated. Specify attenuation to prevent the waveform from being saturated.
The attenuations that you can select vary depending on the pulse width, as shown in the following
table.
Pulse Width
Selectable Attenuations
3 ns to 50 ns
0 dB, 2.50 dB, 5.00 dB, 7.50 dB, 10.00 dB, 12.50 dB, 15.00 dB
100 ns to 1
μ
s
0 dB, 2.50 dB, 5.00 dB, 7.50 dB, 10.00 dB, 12.50 dB, 15.00 dB, 17.50 dB, 20.00 dB
2
μ
s to 5
μ
s
0 dB, 2.50 dB, 5.00 dB, 7.50 dB, 10.00 dB, 12.50 dB, 15.00 dB, 17.50 dB, 20.00 dB,
22.50 dB, 25.00 dB
10
μ
s
0 dB, 2.50 dB, 5.00 dB, 7.50 dB, 10.00 dB, 12.50 dB, 15.00 dB, 17.50 dB, 20.00 dB,
22.50 dB, 25.00 dB, 27.50 dB, 30.00 dB
• If the distance range or pulse width is set automatically, or if the average method is set to high
reflection, you cannot select the attenuation.
• If the waveform is saturated, you cannot perform measurements with high sensitivity, so specify a
large value.
Sample Interval
The maximum number of sample data points is 100,000. The shortest sample interval is determined by
the distance range.
Normal: The AQ1200 uses the optimum sample interval for the measurement method to
perform measurements.
Hi-Resolution: The AQ1200 uses the shortest sample interval to perform measurements.
If you use a short sample interval, you can measure for finer changes. However, the data size of the
measured result becomes large. The sample intervals that you can select vary depending on the
distance range, as shown in the following table.
Distance Range
Selectable Sample Intervals
500 m
5 cm, 10 cm, 20 cm, 50 cm, 1 m
1 km
5 cm, 10 cm, 20 cm, 50 cm, 1 m, 2 m
2 km
5 cm, 10 cm, 20 cm, 50 cm, 1 m, 2 m, 4 m
5 km
10 cm, 20 cm, 50 cm, 1 m, 2 m, 4 m, 8 m
10 km
20 cm, 50 cm, 1 m, 2 m, 4 m, 8 m
20 km
50 cm, 1 m, 2 m, 4 m, 8 m, 16 m
50 km
1 m, 2 m, 4 m, 8 m, 16 m
100 km
1 m, 2 m, 4 m, 8 m, 16 m
200 km
4 m, 8 m, 16 m, 32 m
3.5 Setting Measurement Conditions
