Calibration Wizard

How to start Calibration Wizard

Using Hardkey/SoftTab/Softkey

1. Press Cal > Main > Smart Cal....

The Calibration Window / Channel

During a Guided Calibration, a 'Cal Window' is created for you to view the connection of calibration standards before standards are measured. This Cal Window uses a new Cal channel that is created and duplicates the settings in the channel being calibrated.  Correction is ALWAYS OFF for the displayed calibration channel. At the completion of the calibration, the calibration channel and window are deleted.

The measurement of calibration standards can be performed while viewing any VNA window configuration you choose. The Cal Window is appended to your Custom Cal Window setting, and all windows are visible and sweeping below the Cal Wizard before the Measure (cal standard) button is pressed. The windows to be viewed and channels to be swept during the cal process are specified using Remote commands. See an example.

Select Ports for Guided Calibration dialog box help

Allows you to select ports to calibrate.

Select Ports  All ports are selected by default. User can select which port to calibrate.

Calibrate Power  Disabled by default. Learn more.

Perform Guided Cal  Check to perform a Guided Power Calibration. Learn more.

Display Smith Chart During Cal  When enabled, reflection measurements will be displayed on Smith Chart during calibration.

Use existing SrcCal when measuring cal standards  When enabled, and the following conditions are met, the user's existing source power calibration array will be used when acquiring calibration standard data:

• The user is performing a vector calibration only (no power).

• A valid source cal is present in the channel being calibrated.

• The user has elected to enable this feature (via GUI or SCPI).

Select DUT Connectors and Cal Kits dialog box help

Allows you to select the connector type and Cal Kit for each DUT port to be calibrated.

Connectors  To change selection, click the connector field for each DUT port.

If your DUT connectors are not listed, you can create your own connector type and calibration kit file. The VNA includes the following example cal kits  that can be used as a template. See Calibration kits for more information.

• If using a gendered (male and female) connector type, select Type A as the connector type.

• If using a connectorless device such as on-wafer probes., select Type B as the connector type.

One Connector  If enabled, then all connectors will be set the same and changing any one of them will change the others.

DUT Gender  To select gender of the connector. If the connector has no gender, the pulldown displays "None".

One Gender  If enabled, then all genders will be set the same, and changing any one of them will change the others.

Cal Kit  Select the Cal Kit to be used to calibrate each test port. The list for each DUT Port displays kits having the same connector type as the DUT.

One Cal Kit  If enabled, then all Cal Kits will be set the same, and changing any one of them will change the others.

Identical ECal models connected?  ECal modules can be distinguished by serial number. This can have implications on your remote SCPI programs.

Modify Cal  Check, then click Next, to Modify Cal (Standards AND Thru Method).

Error dialog box help

The current cal kit does not cover the current frequency range of the measurement. Do one of the following to correct the problem:

Cal Kit Class Category  Choose from SOLT and TRL. Not available with ECal modules. Click Edit to modify the appropriate class assignments.

Frequency  Change the frequency range of the active channel.

Edit  Modify the class assignments so that a different standard is selected.

Back  Select a different Cal Kit that covers the required frequency range.

Cancel  Exit the Cal Wizard

Modify Cal dialog box help

Thru #n

Lists the proposed Thru connections to be made during the calibration process. You can change these Thru connections to better suit your test setup.

• The proposed Thru connections are listed automatically.

• Additional Thru connections can be selected for higher accuracy. Learn more.

Add Thru

Click to add a Thru connection. Learn more

Remove Thru

Select a Thru by clicking the "Thru #N" field or the "1st Port / 2nd Port" field. Then click "Remove Thru". This selection is NOT available if the selected Thru is required for the calibration.

1st Port / 2nd Port

Click to select the two ports to be included in the Thru connection. The order of the port numbers is not critical.

Thru Cal Method

Lists the available Thru Cal methods for the specified port pairs.

Learn about the Thru Cal Method choices.

Cal Type/ Stds

Click to invoke the View / Modify Properties of Cal dialog box

Do orientation - Appears ONLY if an ECal module is selected for use.

When this box is checked (default) the analyzer automatically senses the model and direction in which an ECal module port is connected to the test ports. If power to the ECal module is too low, it will appear as if there is no ECal module connected. If you use low power and are having this problem, clear this check box to provide the orientation manually.

Orientation occurs first at the middle of the frequency range that you are calibrating. If a signal is not detected, it tries again at the lowest frequency in the range.

View/Detect ECal Characterizations - Appears ONLY if an ECal module is selected for use.

Click to invoke the View ECal Modules and Characterizations dialog box. Displays a list of connected ECal modules.

View/Modify Properties of Cal for Ports... dialog box help

Select calibration type

Another chance to change the Thru method.

Learn about the Thru Cal Method choices.

Advanced

Select the cal method for each connector of the Thru pair.

• TRL - Available ONLY when a TRL cal kit was selected for the lowest port number of the port pair.

• QSOLT  Available ONLY when "Defined Thru" or "Flush Thru" is selected. "QSOLT 2 <= 1" refers to the receive port 2 and source port 1(where reflection standards are connected).

• Enhanced Response  Available ONLY when "Defined Thru" or "Flush Thru" is selected."EnhResp 2 <= 1" refers to the receive port 2 and source port 1.

• Transmission Response  Available ONLY when "Defined Thru" or "Flush Thru" is selected, when Mechanical Cal is selected, and when 2 ports are being calibrated. "TransResp 2 <= 1" refers to the receive port 2 and source port 1.

View Modify  Click to invoke the Preview and Modify Calibration Selections dialog box.

Note: Changes made to the Cal Kit through this dialog are temporary that last only for this calibration. To make permanent changes to the Cal Kit, perform Advanced Modify Cal Kits.

Calibration Steps dialog box help

Note: Calibration can be performed with External triggers. Learn more.

As each new cal step prompt appears, the traces are setup for the next standard measurement. Also, sweeps are triggered continuously until the Measure button is pressed. This way you can view the integrity of the standard connection.

Prompts for standards to be measured.

Measure  Click to measure the standard.

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.

If a standard is NOT measured, a warning appears and Done will not be available after the last Cal step.

Note: Smart (Guided) Cal allows you to measure calibration standards in any order. However, you must click Next and Back without measuring standards until you get to the standard you want to measure.

Sliding Load Measurement dialog box help

Allows you to measure the sliding load standard.

To Measure a Sliding Load:

1. Connect the sliding load to the measurement port following the procedure described in the Calibration Kit User’s and Service Guide.

Note: Do NOT set the center conductor to be an interference fit with the center conductor of the testport.

2. Position the sliding element, then click Measure. Do not move the sliding element until measurement is complete.

Note: The direction in which the slide moves is NOT important. You can start with the slide at the front and move it backward or start at the back and move it forward. To minimize stability errors it is important to start at one end and move it in the same direction for each of the measurement steps.

3. Measure the sliding load for at least five positions for best accuracy.

Note: The positions of the sliding element should cover the full length of the slide, but be unequally spaced to reduce the possibility of overlapping data points. Most sliding loads have marks for each slide position.

4. Click Done after the final measurement.

5. Disengage sliding load lock (if available), and remove sliding load from the measurement port.

6. Measure the remaining standards.

How to Verify Sliding Load Calibration Measurements

Once the calibration is completed, the sliding load can be measured again. The magnitude of the return loss should remain nearly constant as the slide is moved. If the slide spacing was not adequate due to slide position selections, there will be frequency ranges where the magnitude will not remain nearly constant.

Specify delay dialog box help

This dialog appears ONLY when Adapter Removal or Unknown Thru calibrations are performed.

The following values were estimated from the measurement. Most of the time, they are adequate. However, for CW sweep or frequency sweep with large step sizes, the accuracy of the values may be improved.

Adapter delay  To improve this value, measure and record the delay of the adapter with a dense step size. Enter that value here. The required precision value is the accuracy that is required to characterize the delay value.

Nominal phase offset  (Waveguide ONLY). To improve this value, measure and record the phase offset of the Waveguide adapter with dense step size. Enter that value here.

When one connector is coax and the other connector is waveguide, the phase offset has an ambiguity of 180 degrees. For consistency, the estimate provided here is always between 0 and 180 degrees. You can change this estimate to any value between -180 degrees and +180 degrees.

Unguided Cal dialog box help

When the Perform Guided Cal is unchecked, this dialog box is displayed.

Connect the each standard one by one and click the corresponding standard button.

Save As Calset... Its grayed out when calibration is incomplete. Once the calibration is completed, press this button to save the calibration.

Basic Calibration

Using Hardkey/SoftTab/Softkey

1. Press Cal > Main > Other Cals.

2. Select Basic Cal....

Basic Cal dialog box help

Connector Type Allows user to select single connector type.

Cal Kit Allows users to select single Cal Kit. The displayed selection options are according to the selected connector type.

Port  Allows users to select the port gender. No Connect indicates that no port is connected to the VNA.

Cal Type Allows users to select calibration type. The displayed selection options are according to the selected cal kit, connector type and gender.

Save As Calset... Its grayed out when calibration is incomplete. Once the calibration is completed, press this button to save the calibration.

Unguided Calibration

Using Hardkey/SoftTab/Softkey

1. Press Cal > Main > Other Cals > Response Cal....

Select Calibration Type for Mechanical Standards dialog box help

Unguided calibration does NOT support cals greater than 2 ports or ECal calibrations.

Calibration Type Selection

• 2-Port SOLT

• 1-Port SOL

• TRL - Learn more about TRL

• Response - Reflection and Thru (if the active measurement is transmission)

Cal Configuration  If not calibrating all test ports, specify which ports to calibra te.

Back  Return to Cal Wizard Begin dialog.

View/Select Cal Kit  Click to invoke the Select Cal Kit dialog box.

Note:  When selecting a Cal Kit with an impedance other than 50 ohms (Waveguide = 1 ohm), it is NO LONGER NECESSARY to change the System Impedance setting before performing a calibration. The impedance for the calibration is now derived from the Cal Kit impedance.

Next  Click to continue to Measure Mechanical Standards dialog box.

Select Cal Type dialog box help

This dialog box appears ONLY when the selected Cal Type is TRL in the previous dialog box.

TRL Reference Plane  Select which standard to use to establish the position of the measurement reference plane.

THRU Standard  Select if the THRU standard is zero-length or very short.

REFLECT Standard  Select if the THRU standard is not appropriate AND the delay of the REFLECT standard is well defined.

TRL Impedance

LINE Standard  Specifies that the characteristic impedance of the LINE standard should be used as the system impedance.  This ignores any difference between Offset Z0, Offset Loss, and System Z0.

SYSTEM Impedance  Transforms the LINE standard impedance and loss to that of the system impedance for use with the calibration error terms. The TRL calibration will first compute the error terms assuming the LINE standard impedance is the system's characteristic impedance (same as previous LINE selection), then modify the error terms to include the impedance transformation. This should only be used with coax since the skin effect model used is a coaxial model.

Learn how to change System Z0.

To learn to substitute other calibration kits, see Advanced Modify Cal Kits

Select Cal Kit dialog box help

Displays the calibration kit files available for Unguided calibration. Select the desired calibration kit file and click OK.

Choose class type

Edit Class Assignments  Allows modification of the selected Cal Kit class assignments.

• To learn to substitute other calibration kits, see Advanced Modify Cal Kits

• Unguided Cal can access only mechanical cal kits #1 through #95, although more cal kits can imported. Learn how.

Note: When selecting a Cal Kit with an impedance other than 50 ohms (Waveguide = 1 ohm), it is NO LONGER NECESSARY to change the System Impedance setting before performing a calibration. The impedance for the calibration is now derived from the Cal Kit impedance.

Measure Mechanical Standards dialog box help

Note: Calibration can be performed with External triggers. Learn more.

Displays the calibration kit file and standards required for the calibration.

• Standards may be connected and measured in any order.

• Connect the standard to the measurement port and click its associated green button. A check mark indicates the standard has been measured.

• If a standard type contains multiple standards, the Multiple Standards dialog box opens to display the multiple standards included in the calibration kit file.

• If a sliding load is included in the calibration kit file, the Sliding Load dialog box opens to perform the measurement with the standard.

• Reflection Response  Select EITHER Open or Short standard, then click Next.

• Isolation  Requires one load for each test port. Learn more about Isolation.  Use when your measurement requires maximum dynamic range (> 90 dB). See also Isolation Portion of 2-Port Calibration.

• Normalize  Available when performing a response cal for any measurement. After Normalize is pressed and the Cal is complete, the data trace is flat when the same physical connections are present on the port. This is similar to Data/Memory, except that the response cal is saved with Cal data and can be applied to other like measurements. Data/Memory is still available after using Normalize. You would usually connect a THRU standard when calibrating a transmission measurement, and a SHORT standard when calibrating a reflection measurement.

Show Prompts  Check to provide a reminder for the required connection when you click on the standard.

Multiple Standards dialog box help

Select the standards to be measured.

Note:  You may see both male and female standards. The Unguided cal has no knowledge of the gender of your connector types. Choose the gender of your DUT connector; NOT the test port. Then click OK.

To modify this calibration class to show only one standard, on the Calibration menu, click Advanced Modify Cal Kits. Select the Cal kit and click Edit Kit. In Class Assignment, click Edit. Learn more about Modify Calibration Class Assignments.

• Connect the standard to the measurement port and click its associated button. A check mark in the Acquired box indicates the standard has been measured.

• To cover the entire frequency range, you may need to measure more than one standard. The order in which the standards are measured is important. The last standard that is measured will override the others in respect to the frequency range of the standard definition. Example: In the case of measuring both a broadband load and a sliding load, you would measure the sliding load last. This is because the frequency range of the sliding load is a subset of the broadband load.

Calibration Completed dialog box help

Finish  Save to the channel's calibration register.

Save As User Cal Set  Invokes the Save as User Cal Set dialog box AND save to the channel's calibration register.

Cancel  Calibration is NOT applied or saved.

Learn about Calibration Registers.

Learn about User Cal Sets

Copy Cal Set dialog box help

Existing Cal Sets  - Lists the previously-saved Cal Set names.

to  Specify a name for the new Cal Set. Either accept the suggested new name, type a new name, or select a name from the list to overwrite an existing name.

OK  Saves the Cal Set to the new Cal Set name and exit the dialog message.

Learn about User Cal Sets