5-12
IM AQ7280-01EN
Unit
Set the optical power display unit from the following. dB (absolute value), dBm (absolute value), W
(absolute value)
• Unit W is preceded by a prefix m(10‒3), μ(10‒6), n(10‒9), or p(10‒12).
• The following relation holds between the absolute display unit dBm and W.
PdBm = 10×log(Pw×10‒3)
PdBm: Optical power (unit dBm), Pw: Optical power (unit W)
Reference
You can set a reference value and display the relative measured values (the differences from the
reference value).
• When you press the DREF soft key, the displayed measured value becomes the reference value.
From this point, relative values will be displayed. The unit changes to dB.
• When you press the DREF soft key or set the unit to dB, the Reference box appears on the
power meter screen.
• You can set the reference value in the Reference box. The range is –80to 40 dBm.
• When you set the unit to dBm or W, the Reference box disappears, and the absolute measured
values will be displayed.
Bar Graph and Threshold Display
The upper and lower threshold values specified on the optical power meter setup screen are
displayed with broken lines. While the bar is within the threshold boundaries, it is displayed in
green. Otherwise, it is displayed in red.
Setting Detailed Measurement Conditions
1.
From the top menu, select
Power Checker
to display the following screen.
2.
Press
SETUP
to display the following screen.
Set the offset (-9.900 to 9.900 dB).
See page 5-5.
Set the threshold (-80 to 40dBm).
Set the upper and lower limits.
See page 5-5.
Note
With the /PC option of the OTDR unit, you cannot save measured data to files. If you need to save data, use
the OPM module, explained earlier.
5.2 Measuring Optical Power (OPM, /PC option)