This adjustment is used to maximize the RF output power of the A8 Low Band Output in digital mode operation.
First, I and Q drives are set to known levels and checked using the ABUS. Digital modulation is turned on and the low band detector output voltage is connected to the ABUS. Next, the Pulse Mod, ALC, and Gain Adjust DACs are each set to specific levels and the output is verified using the ABUS. Next, the Mixer Bias DAC is adjusted for the maximum voltage on the low band detector output. Finally, the Mixer Bias DAC counts are reduced by a fixed amount to minimize internal modulation distortion and the new values are 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.