EXFO FTB -5240S/5240BP Optical Spectrum Analyzer - Manual (Page 269)

Managing Results
OSA 263
Managing WDM Test Results
When the acquisition is taken (see Starting a Measurement on page 237 for
details on how to perform a test), the active trace will be displayed in the
tab with information along the following axis values:

X axis: wavelength in nm or frequency in THz.

Y axis: optical power expressed in dBm, as measured in the optical
resolution bandwidth (RBW) of the OSA. This reference RBW is shown
at the bottom of the graph.
If the current active trace was previously saved, the application will display
the file name of the current trace in the title bar.
The graph will display peak indicators for all the channels found by the
application with a red vertical line over the peaks to indicate the peak
position.
A blue horizontal bar ( ) will be displayed on the top of a channel if it
does not overlap with another channel. If the channel overlaps with
another channel, the horizontal bar will be yellow (
).