EXFO FTB -5240S/5240BP Optical Spectrum Analyzer for FTB 500 (NS-1434) - Manual (Page 327)

Managing Results
Optical Spectrum Analyzer 319
Managing WDM Test Results
4. Enter values in the boxes as explained below:
³
Wavelength/Frequency (nm/GHz): indicates the channel’s central
wavelength/frequency.
³
Signal power (dBm): indicates the signal power for the selected
channel (excludes noise).
³
OSNR (dB): is the 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).
³
Noise (dBm): indicates the level of the noise for the selected
channel.
5. 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.