Batched & N-Port (Multiport) Reference Plane Adjustment


These TWO dialogs allow you to adjust the reference plane for up to 64 ports. Adapters, fixtures, or probes that are used to measure your DUT introduce errors such as additional loss, phase shift, and mismatch. After measurements are performed, these unwanted effects can be removed mathematically using the Reference Plane Adjustment features.

  1. The Batched Reference Plane Adjustment dialog allows adjustments to multiple files at the same time.

  2. The standard N-Port Reference Plane Adjustment dialog allows adjustments to only the active file.  Adjustments are saved to the *.DUT file using File, Save As.

How to select Batched Reference Plane Adjustment

Apply de-embedding, port rotation, and port impedance to several files at the same time.

Click Utilities, then Batched Reference Plane Adjustment

Batched Reference Plane Adjustment dialog

Except for the two additional steps (in red above), this dialog is identical to the standard N-Port Reference Plane Adjustment below. See that help section for the steps not covered here.

1. Select Files for Adjustment  Click Add then navigate to select files on which a reference plane adjustment is to be  performed.  Click Remove to delete a file that has already been added.

Any number of files can be added.

5. Output File Type  Select the output file type from the drop down menu. See table below.

6. Output File Data Format - Select the output file data format based on the output file type selection. See table below.

Output File Type

Output File Data Format

PLTS DUT File(*.dut)

N/A

Citifile

Real, imaginary

Magnitude, angle

dB, angle

Touchstone 1.0

Magnitude, angle

dB, angle

Real, imaginary

Touchstone 2.0

Magnitude, angle

dB, angle

Real, imaginary

TDA MeasureXtractor

dB, angle

Cadence Allegro

dB, angle

Text(tab delimited)

Real, imaginary

Log Magnitude

Linear

Phase

Text(comma delimited)

Real, imaginary

Log Magnitude

Linear

Phase

 

7. Output Directory  Click Browse, then navigate to a directory to which the new 'adjusted' file will be saved. Change the default directory using the User Preference File Storage Location feature.

Same directory as input files - Check to save files to the input file director.

Note: If all port impedances are the same, after transform the system Z0 will be set to the port impedance.

 

How to select N-port Reference Plane Adjustment  

Click Utilities, then N-port Reference Plane Adjustment

N-Port Reference Plane Adjustment dialog

Select Adjustment Method

De-embedding / Embedding

  • De-embedding mathematically REMOVES the effects of characterized device, such as an adapter or fixture, from the measurement.

  • Embedding mathematically ADDS the effects of the characterized device to the measurement.

The device must be already characterized and stored in an *.sNp file, *.cit file, or *.DUT file. While measuring the device provides the most accurate characterization, it may be difficult or impossible to perform the measurement due to connectivity issues. In these cases, S-parameter models may offer the best alternative. See also PLTS Adapter Characterization tool.  When using the De-embed / Embed feature, you must know the orientation of the ports as the device was characterized.

Note: Beginning with PLTS2016, 3-port DUT configurations are supported. These are devices that convert a single-ended input to a differential output.

Reverse De-embed / Embed File Reverses, or 'mirrors' the device port numbers as they are applied to the DUT port.

The following image shows a characterized 2-port device on the input and output of a 2-port DUT. The 2-port file on the output is  'Reversed'.

  1. Specify location of the file to de-embed   Click ... (browse) and to navigate to your  *.citi, *.DUT, or *.sNp file, where N is the number of ports that are characterized in the file.

  2. Select Ports   Select a port labeled 'none' to which the specified file will be applied. The file is applied to the ports below the selected port. For example, with a 6-port file to embed or de-embed, and port 2 is specified, click Add Specified Adjustment and the file is applied to ports 2,4, and 6. If there are fewer DUT ports than ports in the specified file, an error message is displayed.

  3. Apply or Remove  Click to Add or Remove the adjustment to the specified ports.  

  • Remove All Reference Plane Adjustments  Removes all of the adjustment methods from all ports. It also clears the reverse orientation check box settings. However, it will NOT remove any adjustments that are currently applied to the active .dut file.

Port Rotation / Extension

Allows you to move the calibrated reference plane from the end of the test cable toward the DUT to eliminate the effects of phase shift introduced by the addition of adapters, fixtures, and probes. Port rotation does not correct for additional loss and mismatch introduced by these items.

  1. Specify Rotation   Enter the rotation in millimeters (mm). The equivalent time in picoseconds (ps) is also displayed.  

    • Enter positive values to move the calibration reference plane closer to the DUT.

    • Enter negative values to extend the reference plane away from the DUT.

    • You may enter real numbers between -50000.0 mm and 50000.0 mm.

    • Click Up/Down arrows to change in 0.1 mm increments, or enter values to 11 places to the right of the decimal using the keyboard.

  1. Select Ports   In the Rotation column, select a port to receive the rotation value. Each port may be assigned unique values.

  2. Apply or Remove  Click to Add or Remove the adjustment to the specified ports.  

  • Remove All Reference Plane Adjustments  Removes all of the adjustment methods from all ports.  However, it will NOT remove any adjustments that are currently applied to the active .dut file.

Port Reference Impedance  

By default, all ports are set to 50 ohms impedance. This adjustment mathematically transforms the measured data to show the performance of the DUT in the specified impedance.

  1. Specify the impedance in ohms  Enter real numbers between 0.0 ohms and 1000.0 ohms by 0.1 ohm increments using the Up/Down arrows. You can enter values to 11 places to the right of the decimal using the keyboard.

  2. Select Ports  In the Impedance column, select a port to receive the Impedance value. Each port may be assigned unique values.

  3. Apply or Remove  Click to Add or Remove the adjustment to the specified ports.  

    • Remove All Reference Plane Adjustments  Removes all of the adjustment methods from all ports.  However, it will NOT remove any adjustments that are currently applied to the active .dut file.

Diff/Com Port Reference Impedance  

The differential and common mode impedances are de-coupled and can be changed independent of the single-ended impedance. Typically, differential and common mode parameters are computed based on the single-ended S-parameters. However, when the Diff/Com Port Reference Impedance setting is selected, the single-ended S-parameters will be computed based on the mixed mode parameters.

The following is an example showing how to set up, save, and import mixed mode parameters.

  1. Define mixed mode parameters:

    1. Select Utilities > N Port Reference Plane Adjustment.... The N Port Reference Plane Adjustment dialog is displayed.

    2. Select Diff/Com Port Reference Impedance.

    3. Enter the desired impedance value for the differential impedance.

    4. In the Impedance columns, select the Dx: entries then click the Add Specified Adjustment button. The Dx: impedance corresponds to the differential port.

    5. Enter the desired impedance value for the common mode impedance.

    6. In the Impedance columns, select the Cx: entries then click the Add Specified Adjustment button. The Cx: impedance corresponds to the common mode port.

    7. Click the Apply button to apply the settings or click the Remove Specified Adjustment button to remove selected settings or click the Remove All Reference Plane Adjustments button to remove all settings.

    8. Click the Close button.

  2. Save Diff/Com Port Reference Impedance Settings:

  1. Select File > Export....

  2. In the Export Data dialog, select Mixed Mode.

  3. Click the Browse button to export the data to a file of your choice.

  4. Click the Export button.

  1. Import the Diff/Com Port Reference Impedance Settings:

  1. Select File > Import... > Single File. The Import a Single File dialog is displayed.

  2. In the Import a Single File dialog, click the Browse button.

  3. Open your data file.

  4. In the Import a Single File dialog, click the OK button.

  5. Select the Frequency Domain (Balanced) analysis view then click the OK button.

  1. Computing Single-Ended Parameters:
    At this point, the mixed mode parameters have been imported in the Frequency Domain (Balanced) analysis view but the single-ended parameters have not been computed based on the mixed mode settings. The following shows the process for computing the single-ended parameters. For purposes of this example, the mixed mode file is called MyMixedMode.s4p.
  1. Select Frequency Domain (Single-Ended) analysis view.

  2. The MyMixedMode.s4p file should be displayed:

  3. In the Parameter Format Selection, click the ALL button to display the single-ended plots. PLTS has now computed the single-ended parameters based on the mixed mode parameters.

  4. In the Parameter Format Selection, use the Dut File drop down menu to select the original file.

  5. Click on the All Data Sharing button to overlay the original single-ended plots onto the MyMixedMode.s4p plots.

  6. Verify that the plots in the MyMixedMode.s4p file (blue) are different from the original plots (red).

 

Apply  Applies the adjustments to the active plot window. The data displayed on the views will then be updated.

Close  Closes the dialog box.

 

Click File, then Save to save the adjustments to the *.DUT file. When the *.DUT file is loaded again, the appropriate status bar indicators on the status bar will be highlighted, and the dialog box will open with the list boxes and reverse orientation check boxes initialized appropriately.

 

The De-embedding indicator on status bar shows when the listed ports have de-embedded data.

The Port Rotation indicator on status bar is shows that at least one port has been rotated.


Last Modified:

3-Dec-2018

Added Diff/Com Port Reference Impedance

26-Feb-2008

Added N-port de-embed