This adjustment calibrates the ALC modulator pre-level circuit on the A23 Low Band Coupler/Detector. The prelevel circuit maintains a constant power level to the low band ALC modulator.
During this adjustment, no test equipment is required. In a known condition, the available power to the ALC modulator is measured using the ABUS circuit and then set to a targeted level using the PRE_LEVEL_DAC. Next, the overall power level out of the low band loop is set using the GAIN_ADJUST_DAC. The next frequency point is selected and the routine repeated. After all frequency points have been measured, the calibration data is stored.
Connect a GPIB cable between the controller and the signal generator being calibrated.
While performing this adjustment, follow all instructions on the controller display.
If this adjustment fails, perform the following steps in order:
Verify that the GPIB cable is connected between the controller and the signal generator being calibrated and rerun the adjustment.
If this adjustment still fails after step 1, refer to the troubleshooting section of the signal generator's service guide. If you do not have a printed copy of the service guide (Option OBW), one is available either on the CD-ROM that came with your signal generator shipment or on the Keysight Website.
If you cannot correct the problem using the troubleshooting procedures in the Service Guide, obtain service from Keysight Technologies. Refer to Contacting Keysight Technologies.