EXFO FTB -5240S/5240BP Optical Spectrum Analyzer for FTB 500 (NS-1434) - Manual (Page 209)

Setting Up the Instrument in Spectral Transmittance Mode
Optical Spectrum Analyzer 201
Setting Up Spectral Transmittance Analysis Parameters
3. Under Global analysis parameters, define the following parameters
as needed:
³
Channel definition (GHz): indicates the limit inside which the
power values will be considered in the channel.
Centred on max peak: Channel is centered on the lowest
insertion loss peak.
ITU Grid: Select the nearest ITU channel from the peak with
lowest insertion loss.
CWDM: Select the nearest CWDM channel from the peak with
lowest insertion loss.
Custom: Channel is centered on value specified by the user.
³
Nominal wavelength or frequency (nm or Thz): indicates a
single value that represent the channels center wavelength (in nm)
or frequency (in THz). This field is editable only when Channel
definition is selected as Custom.