EXFO FTB-5230S Optical Spectrum Analyzer for FTB 200 v2 - Manual (Page 112)

Setting Up the Instrument in Drift Mode
106 FTB-5230S/-OCA
Defining Preferences
2. Select the Drift Results tab.
3. Select which parameters you want to display in the Channel Graph
tab from the list of available choices:

Center wavelength/frequency: spectral center-of-mass for the peak
in that channel.

Signal Power: signal power for the selected channel (excludes
noise).

OSNR: Optical Signal to Noise Ratio, given by Signal power
(according to the current calculation method, in dBm) minus
Noise (according to the current calculation method, in dBm).
4. Press OK to save the changes and close the window, or press Cancel to
exit without saving.
Press Restore Defaults to remove all the changes and apply the default
values.