HP 83487A User Manual page 50

Calibration Overview
User Calibrations—Optical and Electrical
To initiate a dark calibration
1 Press the Display key. Press the Color grade softkey, and set its setting to on.
Color grade must be enabled to perform an extinction ratio measurement and
a dark calibration. In addition, the dark level (amplitude when there is no signal
present) must be on the screen to perform a dark calibration.
2 Press the blue shift key, and then the Meas eye softkey which is located beneath
the display.
3 Press Extinction ratio ... and then Dark cal.
Disconnect all inputs from the module, including the trigger signal, and block
any ambient light to the photodetector with a connector plug. Follow the
instructions on the screen.
Figure 3-4. Dark calibration menu
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