Agilent Technologies E4438C - Manual (Page 127)

Adjustments
ALC Modulation Driver Bias Calibration
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ALC Modulation Driver Bias Calibration
Description
This calibration adjusts the ALC MOD DRV BIAS DAC on the A13 Output. This DAC is used to control the
bias current to the ALC modulator driver. It is primarily used to accommodate unmatched V
BE
values in the
drives, but has a strong influence on modulator gain. This test adjusts the DAC until the ALC modulator gain
is balanced around its nominal design center. The results are stored as a calibration array in the signal
generator’s firmware.
Required Test Equipment
• None
Procedure
1. Preset the signal generator.
2. Follow the instructions as they appear on the controller’s display.