This technical note describes how to configure the SPARQ to measure mixed-mode S-parameters for a system with two differential ports. First, open the SPARQ Ports Config by clicking the Configure button in main Setup dialog. Also check the Enable checkbox as shown.

Typical Use Case: 2-port Differential S-parameters

  1. After opening the SPARQ Ports Config window (last page), click the grey rectangle with the text DUT to open the SPARQ Configure DUT dialog, and configure the popup:
    • Num Ports = 4
    • On Left = 2
    Then click OK to continue
  2. Next, configure the SPARQ Ports Config screen:
    1. Configure the selectors in each green rectangle to correspond to the SPARQ ports connected to each differential pair. The configuration shown has ports 1 & 2 and 3 & 4 being +/- differential pairs, with 1 & 3 being the + sides, and 2 & 4 the - sides.
    2. The blue selectors determine the port numbering of the differential ports, and are configured so that SPARQ ports 1 & 2 are considered differential port 1, and SPARQ ports 3 & 4 are differential port 2.
    3. The orange selectors determine the matrix ordering, and are configured so that the S-matrix has all differential-todifferential S-parameters in the upper-left quadrant, all common-mode-to-common-mode S-params in the lowerleft, and the mixed-mode in the lower-left and upper-right.
  3. When complete, click the Apply toolbar button. Then, in the main SPARQ application window, click Go to take a measurement, or Recalculate to re-analyze the currently acquired data with the new setup.