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Eye-Diagram Analyzer Reference
Calibrating the Eye-Diagram Analyzer
Calibrating the Eye-Diagram Analyzer Note For information on user-corrections and instrument calibration data, refer to
“Agilent 70820A User-Corrections” on page 3-49 and refer to “Agilent 70820A
Calibration” on page 3-61.
To Compensate
for dc Offsets An offset calibration routine is provided that allows th e e ye-diagram analyzer
to compensate channel 1 for any external or internal dc offsets. Thi s ensures
accurate measurements of the laser’s one and zero levels. For example, you
can use the calibration to remove any offset that may be present in an optical-
to-electrical converter. This is sometimes referred to as the "dark" level.
To perform an offset calibration
1Turn the laser off and then press:
Trg, Cal, OFFSET CAL, CONT
The calibration takes about a minute to execute. When the calib ra t ion is
finished, DC NULL: done is displayed.
2Turn the laser on.
To Calibrate IF
for Accuracy The 70820A microwave transition analyzer module provides separate auto-
matic IF calibration routines for channel 1 and channel 2. Each requires
approximately 30 minutes to run. For optimum performance, you should per-
form the calibrations when at least one of t he following is true:
•The temperature has changed ±5° Centigrade since the last calibration was
performed.
•More than one week has passed since the last calibration.
•Before any critical measurement.
CAUTION Allow the microwave transition analyzer module to warm up for at least one
hour before performing a calibration.