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IM AQ1200-01EN
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App
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1.4 Waveform and Event Analysis
Waveform Analysis
You can use the cursor and markers to measure values such as the distance, splice loss, return loss,
or reflection level between two points.
Measuring Distance
The AQ1200x/AQ1205x measures the time that it takes for an incident optical pulse to be reflected and
return to the device. It uses this information and the following equation to calculate the distance (L).
L = C×T/(2N) [m]
C: The speed of light in a vacuum 2.99792 × 10
8
[m/s]
T: The time measured from when the incident pulse was generated to when the reflected light
was received [s]
N: Index of refraction
In the above equation, the division by two accounts for the fact that the measured time represents the
total time taken by the optical pulse to reach the reflection point and to return from it.
If the correct index of refraction is not specified, there will be errors in the distance measurement.
Setting the Index of Refraction
The AQ1200x/AQ1205x has preset indices of refraction that correspond to each wavelength. For
details on the settings, see section 3.6. Contact the optical fiber manufacturer for the fiber’s correct
index of refraction.
Distance Range
You must select a distance range that is longer than the cable length of the optical fiber that you
want to measure. As the distance becomes greater, the measurement time also increases. For
details on the setting range, see section 3.5.
Pulse Width
There are the following features depending on the length of the pulse width. The pulse width that
you can select varies depending on the distance range that you have specified. For details on the
settings, see section 3.5.
• Short pulse width
You can separate and measure adjacent events (reflection points and losses). However, you
cannot measure long distances.
• Long pulse width
You can measure long distances. However, multiple adjacent events may be seen as one single
event.
Pulse width
