EXFO FTB -5240S/5240BP Optical Spectrum Analyzer for FTB 500 (NS-1434) - Manual (Page 243)

Setting Up the Instrument in EDFA Mode
Optical Spectrum Analyzer 235
Setting Up EDFA Analysis Parameters
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Peak detection level (dBm): indicates the minimum power level
from where the peak can be considered as a signal.
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RBW for OSNR (nm): indicates the resolution bandwidth for the
selected OSNR value. The resolution bandwidth of an OSA
determines its ability to deal with close optical channel spacing. It
is measured as the width of the response curve at half peak power
(i.e., 3 dB down) of the instrument to a monochromatic test signal.
The instrument’s RBW value is written below the graph on the right
(below wavelength offset).
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Input wavelength offset (nm): indicates the offset value applied
on the input wavelength. You can use an offset to adjust your unit.
This does not replace a calibration performed at EXFO, but it can
help you achieve the specifications if you have determined that, for
example, your modules are used beyond the normal allowed.
Entering a value in THz is not possible. The wavelength offset
appears below the graph, on the right, next to the
arrow.
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Input power offset (dB): indicates the offset value applied on the
input power. You can use an offset to adjust your unit. This does
not replace a calibration performed at EXFO, but it can help you
achieve the specifications if you have determined that, for
example, your modules are used beyond the normal allowed. The
power offset appears in the graph, on the left, above the
arrow.
To edit the power offset value in percentage, press Edit % button.
The percentage value entered in Edit percentage will be
converted to a corresponding equivalent value in dB.