Dark Level Calibration

The Dark Calibration calibrates Eye/Mask mode's NRZ Extinction Ratio measurement (:MEASure:EYE:ERATio command) and PAM/NRZ Output Extinction Ratio measurement (:MEASure:EYE:OER command). These measurements are performed on optical channels.

Calibration commands correspond to the features in the Calibration dialog. You can click on the tabs in this picture to learn about the different calibrations.

The calibration identifies internally generated offset (dark level) signals generated by external optical-to-electrical converters and removes them during the extinction ratio measurement calculations. The dark calibration applies to the currently selected filter rate for a channel. If a new filter rate is selected, you must perform another dark calibration. Prior to performing a dark calibration, adjust the vertical scale and offset so that the eye diagram uses the full display. Also, the dark level (the signal level when there is no input to the measurement) must be on the screen to be correctly measured.

To perform a dark calibration, use the :CALibrate:DARK:CHANnel:STARt.

To query the status of a dark calibration, use the :CALibrate:DARK:CHANnel:STATus? command.