CalPod as ECal


A CalPod module can be used as 1-port ECal module to calibrate channels for all measurement classes. In addition, the CalPod module can be left in place during measurements in order to refresh calibrations.

Note: Before using a CalPod module, ensure that Factory Cal is set to OFF (Cal > Main > Factory Cal OFF).

In this topic:

More Calibration topics

Overview

To use a CalPod module as a calibration device:

  1. The CalPod module must be configured using the CalPod software. Learn how.

  2. Unlike an ECal module, a CalPod module has no internal memory and therefore, no internal characterization data. Before a CalPod can be used as an ECal module, its internal standards must first be characterized using the ECal User Characterization wizard.  In addition, the characterization data can ONLY be stored in VNA disk memory.

  3. After these steps have been performed, connect the CalPod modules to the controller to perform a VNA calibration. The CalPod modules will appear in Cal Wizard dialogs just like an ECal module.

This image shows TWO CalPod modules after both have been characterized. An additional thru connection is required to complete a 2-port calibration. Subsequent ‘refresh’ calibrations can occur without making additional connections.

Characterizing the CalPod module - Summary

When performing a User Characterization for a CalPod module, you can establish the Calibration reference plane at the input connector, or at the output connector, depending on how you plan to use CalPod.

  1. Initially calibrate the VNA.

  2. After the calibration, the internal CalPod OPEN, SHORT, and LOAD standards are measured.

  3. The measurements are saved to VNA disk memory. They are used when performing calibrations using the CalPod module.

Detailed steps to Perform a User Characterization

Note: If you have more than one CalPod module, each module must be characterized separately.

  1. Perform a one-time CalPod configuration. Learn how.

  2. Connect the CalPod module to the CalPod controller.

  3. Preset the analyzer.

  4. Set up the measurement.  For best accuracy, the IF bandwidth should be set to 1 kHz or less.

  5. Start the User Characterization Wizard as follows:

Using Hardkey/SoftTab/Softkey

  1. Press Cal > Cal Sets & Cal Kits > ECal > Characterize ECal....

 

Select Module and Location dialog box help

ECal Module  Select a CalPod from list of connected modules and registered CalPods.

Detect Connected ECals  Click to rescan CalPod/ECal modules.

Location

Keyboard  Launches a keypad that can be used to type a characterization name from the VNA front panel.

Next  Click to continue to the Select Connectors for the Characterization dialog box.

See note regarding extended frequency use.

 

Select Connectors for the Characterization dialog box help

In situ characterization

When Checked:

  • This initial calibration, and all DUT measurements are performed WITH the CalPod module THRU path in place (In Situ).

  • Only the port with the switchable states is characterized (open, short, load, and offset short). The THRU state is not characterized.

  • Select the RF2 (output) connector type and Cal Kit.

  • The Cal Kit standards are connected to the RF2 Output connector, making it the reference plane. This calibration removes everything in front of the output connector from subsequent measurements.

  • The User Char description will show "In Situ".

  • The CalPod’s states physically switch in at its RF1 port, but for an in-situ characterization the calibration used for measuring the characterized data for those states has its reference plane at-or-beyond the CalPod’s RF2 port. So, for all calibrations subsequently performed using the in-situ CalPodAsECal user characterization, those calibrations also establish the reference plane at that same connector interface at-or-beyond that CalPod’s RF2 output port.

When Cleared:

  • This initial calibration, and all DUT measurements are performed WITHOUT the CalPod module in place. This is similar to an ECal calibration.

  • Select the RF1 (input) connector type and Cal Kit. The Cal Kit standards are connected at this location, making it the reference plane.

Next  Click to continue to the Calibrations to perform or recall dialog box.

 

Calibrations to perform or recall dialog box help

Perform or load a 1-port cal.

Guide me through this cal now  Click to perform a Guided calibration.  A calibration kit is required for each connector type.

Let me recall this cal from a cal set  Click to select an existing Cal Set. You cannot select a Cal Set that is currently in use. Learn more about Using Cal Sets.

Next  Click to continue to either the Select Cal Kits (Perform Cal) or Select Cal Set (Recall Calset).

 

 

Select Cal Kits dialog box help

When 'In situ' is selected, a cal kit is selected for port "RF2", as this will be the calibration reference plane (where standards are connected).

Provides a list of calibration kits to perform the calibration. Select the Cal Kit you will use for the port.

Next  Click to continue to the Select Cal Set dialog box.

 

Select Cal Set dialog box help

The calibration that you perform will be written to a Cal Set. This dialog box allows you to select a Cal Set to overwrite, or to write to a new Cal Set. The current choice is visible below the Select Cal Set button.

Select Cal Set  Click to open the Select A Cal Set dialog box.

Create new Cal Set  Check to create a new Cal Set to store the calibration. Clear to select and overwrite a stored Cal Set.

Next  Click to continue to the Guided Calibration Steps dialog box.

Note: Remember the Cal Set name for future reference.

 

Guided Calibration Steps dialog box help

The first Measure page.

Connect each calibration standard to the location in the prompt.

Measure  Click to measure the standard.

Back  Click to repeat one or more calibration steps.

Done  Click after a standard is re-measured and all measurements for the calibration are complete.

Next  Click to continue to the next calibration step. (Does not measure the standard.)

Cancel  Exits Calibration Wizard.

 

Guided Calibration completed dialog box help

Allows you to finish the calibration and continue to the next characterization steps.

No. Finish now  Select to save Cal Set data.

Yes  Allows selection of Save options.

Next  Click to continue to the Exit to Inspect Quality of Calibration dialog box.

 

Exit to Inspect Quality of Calibration dialog box help

Allows you to exit User Characterization to validate the calibration before proceeding with the characterization.

Back  Allows you to repeat calibration.

Next  Click to continue to the Characterization Steps dialog box.

Cancel  Exits the Calibration.  

To return to the current step:

  1. Start User Characterization.

  2. In the Select Connectors for Characterization dialog box, click Next. (Previous entry is stored in memory.)

  3. In the Calibrations to perform or recall dialog box, recall the Cal Set that you just performed.

 

Characterization Steps dialog box help

After the initial VNA calibration, the CalPod internal states are measured.

Connect the CalPod if not already connected.

Measure  Measures the CalPod module.

Next  Click to continue to the Information for the New Characterization dialog box when measurements are complete.

 

Information for the New Characterization dialog box help

Enter descriptive information that will be stored in the characterization file. This description will be viewable in the several VNA dialogs when the CalPod is selected.

Next  Click to continue to the Write Characterized Data dialog box.

 

Write Characterized Data dialog box help

The VNA writes User Characterization data to the VNA disk memory.

Write  Click to write data.

 

Summary of new User Characterization dialog box help

Summary page of characterization wizard after characterization is complete.

Cancel  Click to exit (characterization complete).

Finish  Click to exit (characterization complete).

Calibrating with CalPod

The CalPod module is now characterized and ready to be used in a VNA calibration.

When CalPod modules are selected for ALL ports of an N-port cal, Unknown Thru is the only selectable Thru method for all paths. Learn more about Unknown Thru.

The above image is the Connectors and Cal Kits page as seen during a SmartCal on a standard channel.  A similar version of this page is shown in the Calibration Wizard for all Application channels .