I/Q Timeskew Baseband
(Option 001, 002, 601, or 602 Only)

This adjustment requires firmware revision C.03.10 or later.

The purpose of this calibration is to determine the I/Q timing skew adjustments required to minimize the I/Q timing skew of internally generated signals on the I/Q external outputs. This adjustment will be required for a number of the unique I/Q baseband paths that exist from the baseband generator through the instrument to the I/Q outputs.

The calibration is accomplished by applying identical multitone baseband signals to the I channel, the Q channel, but 180 degrees out of phase. The I/ Q outputs are then summed together through a tee and the resultant waveform is measured with a spectrum analyzer. The I/Q time skew between the I and Q channels is then adjusted until the signals cancel each other to the maximum extent possible. This point of maximum cancellation will coincide with the point at which the I and Q channels I/Q time skew is minimized.

Required Test Equipment

Test Equipment

Recommended Models

Alternate Models

Spectrum Analyzer

N9030B Opt 5xx1

N9030A Opt 5xx1
E444xA2

BNC Cable
   6" long
   Quantity: 2

Note: For adjustment accuracy, use short, equal-length cables at the I and Q outputs.

 

  1. Select any option of PXA spectrum analyzer (503, 508, 513, 526, 543, 544, 550) that has a maximum frequency greater than or equal to the maximum frequency of the unit under test.

  2. Select any model of PSA spectrum analyzer (E4440A, E4443A, E4445A, E4446A, E4447A, E4448A) that has a maximum frequency greater than or equal to the maximum frequency of the unit under test.

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.

 

Use the two 6" BNC cables to connect the UUT I and Q outputs to the BNC Tee.

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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.