This adjustment generates a DAC value to null the voltage offsets on the A6 Frac-N and A11 Pulse/Analog Modulation Generator.
During this adjustment, when FM is enabled the A6 Frac-N and A11 Pulse/Analog Modulation Generator may generate unwanted voltage offsets. These voltage offsets detune the Frac-N VCO from the desired frequency.
There are two FM Offset DACs, which generate a correction value for the external inputs: internal FM and FM internally grounded. The two external inputs can either be AC- or DC-coupled. With all these different combinations, a total of 13 correction values are generated and stored in FlashROM.
The adjustment algorithm uses a frequency counter to determine the Frac-N nominal frequency. The frequency counter is used to calculate the FM Offset DAC sensitivity (DAC counts/Hz). The correction DAC value is then calculated and stored in FlashROM.
Test Equipment |
Preferred Model |
Alternate Model(s) |
Frequency Counter |
53230A Opt 010 and (106 or 115) |
53132A Opt 010 and (050 or 124) |
|
|
Connect all test equipment as shown.
Connect GPIB cables to all GPIB-controlled test equipment.
While performing this adjustment, follow all instructions on the controller display.
Setup for FM Path Offset Calibration
If this adjustment fails, perform the following steps in order:
Check the equipment setup (see above). If the setup is incorrect, make the necessary corrections and rerun the adjustment.
If this adjustment fails with the equipment set up properly, 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.