EXFO FTB -5240S/5240BP Optical Spectrum Analyzer - Manual (Page 246)

Managing Files and Test Configurations
240 FTB-5240S/S-P/BP
Using the Discover Feature
Discover analysis parameters are established as follows:

The acquisition spectral range is set at 5 nm before the first detected
signal peak, and 5 nm after the last detected signal peak (respecting
spectral range limits).

A channel list is created based on detected signal peaks; default
settings are applied for all channel parameters.

The center wavelength of each channel is aligned with an ITU grid
(200, 100, 50 or 25 GHz for DWDM).

The channel width is determined using the overlap criteria; if two
channels overlap by more than 0.001 nm or 0.001 GHz, then their
widths are reduced to the lower width. If the width of two channels is
at 25 GHz and they still overlap, then the width is not reduced and the
application considers it as a multi-peak signal (like recent modulation
formats for 10 Gb/s or 40 Gb/s) and sets the width of the channel to
50 GHz.
Note: One of the limitations of using the Discover feature is that the channels are
discovered based on the ITU-Grid. All detected peaks will be aligned with
an ITU-channel; the channel width and distance are computed and fit in
one of the ITU grids (25, 50, 100 or 200 GHz). If your channel is not based on
the ITU grid, the results may not be correct. In this case, you can use the
default channel definition or create a new channel list.