EXFO FTB-5230S Optical Spectrum Analyzer for FTB 200 v2 - Manual (Page 81)

Setting Up the Instrument in WDM Mode
OSA/OCA 75
Setting Up WDM Analysis Parameters
3. Select the Activate all thresholds option to manually set the global
threshold values. If this option is not selected, all the thresholds will be
deactivated, results are displayed without a Pass/Fail status and Global
pass/fail status are not active in the Global Results tab.
4. Enter values in the boxes as explained below:

Average signal power (dBm): the sum of the signal powers of all
the peaks detected in the current acquisition, divided by the total
number of peaks.

Signal power flatness (dB): the difference between the maximum
and minimum signal power values of the detected peaks, in dB.

Average OSNR (dB): the sum of the entire OSNR of the peaks
detected in the current acquisition, divided by the total number of
peaks.

OSNR flatness (dB): the difference between the maximum and
minimum OSNR values of the detected peaks, in dB.

Empty channel count: The number of empty channels from the
channel list.