External Input Peak Detector

This adjustment establishes a threshold voltage for the over modulation indicator to turn on. A function generator generates a 1 kHz 1.03 V-peak sinewave to bias the EXT1 and EXT2 inputs. The multimeter measures the RMS value of the function generator to ensure amplitude accuracy. The signal generator FM is enabled and set for 100 kHz deviation.

During this adjustment, there are two EXT_MOD_COMP_DACs on the Reference Board, one for each EXT input. After the hardware is configured, the DACs are set to 0 and increased until the over modulation indicator goes out. The DAC is decreased until the over modulation indicator comes on. The DAC value which causes the over modulation indicator to come on is stored.

When the peak detector level DACs are correctly set, the over modulation indicator will trigger whenever the voltage to the EXT1/EXT2 input is greater then 1.03 volts. If the DAC value is below 20 or above 200, the calibration fails.

Required Test Equipment

Test Equipment

Recommended Model

Alternate Model

Function Generator

33622A

33611A
33612A
33621A

33250A
33120A Opt 001

Digital Multimeter

3458A Opt 002

34470A

Connections and Setup Procedures
  • All test equipment requires a 30 minute warmup period to ensure accurate performance.
  • In the following adjustment 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 1

 

Setup 2

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 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.

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