HP 86140A Series User Manual page 53

Note
The optical spectrum analyzer performs a more complete zeroing when the instrument is
first turned on. You can run this more complete routine anytime by pressing the Zero
Now softkey. Refer to "To zero the instrument" on page 3-50
Auto Chop Mode
Enables the spectrum analyzer chop mode. Chop mode increases dynamic
range for long sweep times by subtracting ambient light. Subtracting the ambi-
ent light can improve sensitivity but slow down the sweep speed.
Pressing the front-panel Preset key turns this function
Note
Sweep times of 50 msec × the # of trace points, or longer, use a special "chop" mode.
Chop mode increases dynamic range, stabilizes measurements against drift, and reduces
effects of stray light. This special chop mode is enabled by setting the Auto Chop mode
to .
ON
Power Calibration
Power Calibration allows you to use amplitude correction factors either from
the factory calibration or from the last successful user calibration. Pressing
the front-panel Preset key resets this function to User. If a user calibration has
not been performed, the factory calibration data is used.
User Power Cal Date
The User Power Cal Date displays the date of the last successful user-per-
formed amplitude calibration. See
page 3-44 for information on performing an amplitude calibration.
Using the Optical Spectrum Analyzer
for more information.
OFF
"To perform a power calibration" on
The Amplitude Menus
.
3-13