Performing Measurements With the InstrumentStudio S-Parameter Measurement Panel

The S-parameter measurement panel in InstrumentStudio allows you to connect a single or dual vector signal transceiver (VST) setup to perform full S-parameter measurements without interacting directly with the S-Parameter Measurement Library API. Use the measurement panel to determine the performance of the device being tested.

The following steps provide a common workflow for interacting with the InstrumentStudio S-parameter measurement panel.
  1. Launch InstrumentStudio.
  2. On the Home screen, select Manual Layout.
    The Edit Layout window appears.
  3. Locate S-Parameters from the Add-Ons list and select Create large panel in the drop-down list for your measurement panel.
    The large panel updates to list the measurement panel.
  4. Click OK.
    InstrumentStudio opens a new project and displays the measurement UI.
  5. Configure settings in the Hardware tab.
  6. Configure settings in the Stimulus tab.
  7. Configure settings in the Measurement tab.
  8. Click File » Save Configuration to store your configured parameters as a .ini file for future use.
  9. Click Connect in the Control pane to open a connection to the hardware.
  10. Click Commit in the menu bar to commit the settings to the hardware.
    The Commit button is enabled only when the application is in an idle state (neither Measuring nor Error state), and you must stop measurement or calibration processes to commit parameters to the hardware.
  11. Click Calibrate and perform system-level calibration using the Calibration Wizard.
    The Calibrate button is enabled only after connecting to the hardware. Refer to Calibrating the System with the InstrumentStudio S-Parameter Measurement Panel for more information about calibration.
    Important To use Keysight calibration kits with the InstrumentStudio measurement panel, use the Calibration Kit SNP File Creator tool to convert *.xkt files to SNP format (.s1p or .s2p). Refer to Converting Calibration Kit Characterizations to SNP Format for more information about using the tool.
  12. Connect your DUT to the input ports of the couplers.
  13. Click Measure to begin the DUT sweep.

    When you click Measure for the first time or after performing calibration, a window appears to remind you to connect the DUT to the couplers before beginning measurement. The Control pane displays DUT Connected after you confirm the connection and click Measure.

    During measurement, the Measure button changes to a Pause button. Clicking Pause stops the DUT sweeps but keeps the connection to the hardware open.

    Note The Measure button is only enabled after connecting to the hardware.
    A pop-up window opens to confirm you have connected your DUT. Click OK to confirm.
  14. View the S-parameter measurements in the Display panes. Use the drop-down menus to select the traces you want to view in each quadrant.
  15. Click Log to store your measured S-parameters as a .s2p file.
    The file saves to the location specified in the Configuration pane.
  16. Once finished, click Disconnect in the menu bar to close the hardware connection.

Configuring Hardware Settings

Refer to the following steps to configure and commit changes to your hardware in the InstrumentStudio S-parameter measurements panel.
  1. On the Hardware tab of the Configuration pane, select your hardware configuration from the Setup drop-down list.
    Making this selection changes the configuration options available to you.
  2. Specify the name of each VST as it appears in Measurement & Automation Explorer (MAX) in the Resource Name drop-down menu(s).
    • If your configuration uses two VSTs, use the Port1 drop-down menu to indicate the VST connected to the input port of the DUT, and use the Port2 drop-down menu to indicate the VST connected to the output port on the DUT.
    • If your configuration uses one VST, the single drop-down menu automatically populates with the name of the VST as configured in MAX.
  3. Configure the power level used to stimulate the DUT using the Power Level (dBm) combo box.
  4. Configure the expected gain to be received at the analysis ports using the External Gain (dB) combo box. This value should include attenuation in cabling, couplers, and other signal conditioning between the transmission and analysis ports of the VST.
  5. If your configuration uses a switch, click the Switch tab at the top of the hardware configuration page and complete the following steps to configure the switches.
    1. Use the Switch Resource drop-down menu to select whether your configuration uses a Single PXI Switch, Single PXI Switch (Solid State), Dual PXI Switch, or External Switches (Solid State).
    2. When Switch Resource is set to Single PXI Switch , Dual PXI Switch, or Single PXI Switch (Solid State), configure the following settings.
      • Configure the device identifiers for each switch as configured in MAX.
      • Configure the connected channels for each switch using the input fields in the Switch Connections section.
    3. When Switch Resource is set to External Switches (Solid State) configure the following settings.
      • Select the digital I/O lines that you want to control the external switches using the Switching Line(s) drop-down menu. When using en external HMC-C058 solid-state switch, the DIO lines are converted from 3.3 V to 5 V.
        • The first line in the list controls the RF output switch. This switch asserts low to switch the generator to port 2, and high to switch the generator to port 1.
        • The second line controls the switch that chooses between the reference or test coupler. This line asserts low to select the test couplers and high to choose the reference couplers.
        • The third line chooses between port 1 and port 2 test coupler. This line asserts low when measuring the port 2 test coupler and high when measuring the port 1 test coupler.
        • The fourth line chooses between the port 1 and port 2 reference coupler. This line asserts low when measuring the port 2 reference coupler and high when measuring the port 1 reference coupler. Refer to the Physical Channel Syntax in the NI-DAQmx User Manual for details on the supported syntax. The high state for these lines is 3.3 V and the low state is 0 V. These lines must be converted from 3.3 V to 5 V when using en external HMC-C058 solid-state switch.
      • Select the DIO line used for the 3.3 V power supply for the voltage conversion circuit from the Power Line drop-down menu.
      • Select the settling time for the RF signal after switching to a new RF path from the Scan Trigger External drop-down menu. When using en external HMC-C058 solid-state switch leave at the default 3E-5 (30 μs).
      • Switch Setting Time (Second): Enter the trigger line used to trigger the switching.

Configuring Stimulus Settings

Refer to the following steps to configure the stimulus characteristics to apply to the DUT.
  1. On the Stimulus tab of the Configuration pane, select a stimulus type of CW Sweep or Pulsed Sweep from the combo box.
    Note Multi-Tone is a placeholder and is reserved for future use.
  2. Configure the Start Frequency (Hz), Stop Frequency (Hz), and Frequency Step (Hz) combo boxes. If performing a pulsed sweep, also configure the Pulse Width (s) and PRI (s).

Configuring Measurement Settings

Refer to the following steps to configure measurement parameters such as IF bandwidth, averaging, calibration data, and data recording path.

  1. On the Measurement tab in the Configuration pane, configure the IF bandwidth of the measurement in the IF Bandwidth (Hz) combo box. The default value is 10 kHz.
    Note Reducing the IF bandwidth reduces the noise in a measurement, but increases the sweep time.
  2. If you want to allow averaging to gain smoother displays and a more accurate measurement, configure the following settings.
    1. In the Average Mode drop-down menu, set averaging to Per Sweep or Per Point.

      Per sweep averaging performs the entire sweep as defined by the stimulus parameters for forward direction first, then repeats the sweep a number of times. Per sweep averaging proceeds to do the same for the reverse direction. Data correction is applied and the corrected data for the different sweeps is averaged together.

      Per point averaging collects multiple records for each frequency step defined for the stimulus. Averaging is then applied on the corrected data.

    2. Configure the Number of Averages value.

      If using per sweep averaging, the Number of Averages value defines the number of times the sweep repeats.

      If using per point averaging, the Number of Averages value defines the number of records collected at each frequency step.

  3. To correct the raw measurement, select a calibration file in the Calibration Data File Path input field.
    The input field automatically populates with a default location that you can change as needed. If this field is left blank, the raw measurement is not corrected. The Status indicator displays the time stamp of the calibration file.
  4. Select a destination location for your calculated S-parameters in the Target File Path field.
    Files are saved to this location in a .s2p format when you click Log in the measurement UI Control pane.