EXFO FTB -5240S/5240BP Optical Spectrum Analyzer for FTB 500 (NS-1434) - Manual (Page 169)

Setting Up the Instrument in Drift Mode
Optical Spectrum Analyzer 161
Setting Up Acquisition Parameters
3. Select the acquisition type.
³
If you are performing a Single acquisition, you cannot modify the
number of scans count value.
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If you are performing an Averaging or In-Band type acquisition,
enter the number of scans the unit will perform.
4. Select the wavelength range for your acquisition.
You can select the wavelength range by entering the start and stop values
or by selecting a range on the double slider.
To select the wavelength range using the double slider, move the left and
right handles on the double slider or simply click on any band.