AM Gain Calibration

(E8257D, E8663D with Option UNT and E8257N Only)

This adjustment calibrates the AM signal paths on the A11 Pulse/Analog Modulation Generator. A total of 16 paths and modes are calibrated. They are derived from two internal sources, two external inputs, two internal paths, and linear and exponential AM modulation modes.

During this adjustment, a function generator in DC mode is used to provide a signal to EXT 1 and EXT 2 inputs for the external path adjustments. The function generator output is also routed to a digital multimeter to ensure the desired DC level is achieved. The A11 Pulse/Analog Modulation Generator provides the signals required for the internal path adjustments.

External and internal linear modes are adjusted for 50% depth (–6.0206 dB). External and internal exponential modes are adjusted for -25 dB depth. Adjustments are made at 3.5 GHz and at a power level of 10 dBm. AM1_DAC and AM2_DAC on the A11 Pulse/Analog Modulation Generator are used to adjust the modulation signal level for the correct RF output level.

Test Equipment

Preferred Model

Alternate Model(s)

Power Meter

N1914A1

E4419B
E4419A

Power Sensor
Only for Opt 520 and 1ED

E9304A Opt H19

E9304A
E9304A H18

Power Sensor
Not required for Opt 520 and 1ED

N8487A

8487A Opt H842
N8485A
N8485A CFT
8485A Opt H842
E9300A Opt H25

Function Generator

33250A

33120A Opt 001

Digital Voltmeter

3458A Opt 002

 
  1. Power meter N1914A with serial numbers ranging between MY00000000—MY53040007 require Service Note 07 to be applied for measurement repeatability. Please have this service note applied or verify it was applied before using this power meter. The affected service note is: N1914A-07 Service Note
  2. Option H84 provides reflection coefficient data.

 

Connections and Setup Procedures

  • All test equipment requires a 30 minute warmup period to ensure accurate performance.

  • In the following test setup, cables are designated as solid lines and direct connections are designated as dashed lines.

  1. Connect all test equipment as shown.

  2. Connect GPIB cables to all GPIB-controlled test equipment.

  3. While performing this adjustment, follow all instructions on the controller display.

 

Setup for Power Meter Calibration (Units with a Type-N RF Output Connector)

 

 

Setup for Power Meter Calibration (All other units)

 

 

Setup for Ext 1 Input (Units with a Type-N RF Output Connector and without Option H42)

 

 

Setup for Ext 1 Input (Units with all other connector types)

 

 

Setup for Ext 2 Input (Units with a Type-N RF Output Connector)

 

 

Setup for Ext 2 Input (Units with all other connector types)

 

 

 

In Case of Difficulty

If this adjustment fails, perform the following steps in order:

  1. Check the equipment setup (see above). If the setup is incorrect, make the necessary corrections and rerun the adjustment.

  2. If this adjustment fails with the setup properly, perform the "AM Audio Path Offset Calibration" and “ALC Dynamic Calibration” and rerun the Adjustment.

  3. If this adjustment still fails after step 1 and step 2, 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.

  4. If you cannot correct the problem using the troubleshooting procedures in the Service Guide, obtain service from Keysight Technologies. Refer to Contacting Keysight Technologies.