This adjustment generates a correction voltage that is used to null any voltage offsets that are created by the A6 Frac-N and A11 Pulse/Analog Modulation Generator when FM is enabled. Without this adjustment, small voltage offsets may be generated that detune the Frac-N VCO from the desired frequency.
During this adjustment, the instrument is set for a 1 GHz carrier at 0 dBm. Internal FM is turned on with the EXT1 FM input left open. The FM Deviation is set for 1 MHz and the FM1 path is selected with DC-coupling. The instrument performs an internal calibration, which generates a frequency-offset value. This value is loaded into a register in an Application Specific Integrated Circuit (ASIC) on the A6 Frac-N.
A frequency counter is used to verify the corrected frequency is within +/- 3% of the theoretical value.
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 DC FM 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.