EXFO FOT-930 Multifunction Loss Tester - Manual (Page 41)

Measuring Power or Loss
Multifunction Loss Tester 33
Referencing Your Power Meter to a Source
Referencing Your Power Meter to a Source
In reference mode, your unit displays the loss
created by the fiber under test only, since it
subtracts a reference value from the measured
power.
In the illustration, the reference value
(-36.87 dBm) is subtracted from the actual power
measured (-7.89 dBm).
Note: The reference value you set for each wavelength remains in memory until a
new one is set for the same wavelength, even when you turn the unit off.
Compatible sources (such as FOT-300 and FLS-300) can transmit a
reference value to your power meter, avoiding the need for manual
referencing. This value is not the source’s actual power. It is a user-defined
value that may not take the link loss into account.