EXFO PM-1100 Optical Power Meter - Manual (Page 27)

Operating the Optical Power Meter
Optical Power Meter 17
Relative Power
When you access relative mode, the Optical Power Meterdisplays the last
reference value entered at the current wavelength. One reference value
can be stored for each wavelength in the shortlist and will remain in
memory until a new reference value is stored at the same wavelength.
However, if you use dB/ΔW, the reference value will be converted from
dBm to watts (and vice versa) when the measurement unit of the relative
power toggles between dB and watts.
Note: If you set a reference while an offset is active, the reference measurement
will take into account the offset (only when using dB measurement units).
Entering the Current Power as the Reference Value
The power of the signal currently received at the detector can be stored as
the reference value.
To enter the current power as the reference value:
1. Use λ to select the wavelength.
2. Use dBm/Watt to select the measurement units.
3. Press Ref.
Relative power
Unit of measurement
for the relative power
Reference value
Unit of measurement
for reference value
nW
nW
A delta symbol indicates
that the PM-1100 is in relative
mode and measuring in watts.