Configure a Power Meter As Receiver (PMAR)


When a power meter is configured as a VNA receiver (in standard measurement channels ONLY), you can...

Note: PMAR is not compatible with Point Sweep mode.

 

Once configured, a power meter can be used like any other VNA receiver in the following dialogs:

See Also

How to Create and Configure a PMAR Device

  1. Create a PMAR device by name (one-time).

  2. Then click Device Properties to configure the Power Meter/Sensor.

VNA Applications have additional methods of launching this dialog.

Using Hardkey/SoftTab/Softkey

Using a mouse

  1. Press Setup > External Hardware > External Device...

  2. Click Device Properties to configure the Power Meter/Sensor.

  1. Click Instrument

  2. Select Setup
  3. Select External Hardware

  4. Select External Device...

 

External Device Configuration dialog box help

This dialog allows you to create and configure a power meter to be used as a receiver by the VNA. Once you create and configure a power meter from this dialog box, it becomes available from VNA dialog boxes as well as the softkeys and entry toolbar, as if it were an internal VNA receiver.

  • This dialog is ALSO used to configure an External Source. Learn more.

  • To configure a single power meter for a Source Power Cal, use the Power Meter Settings dialog.

Important Notes

  • By default, an external PMAR device is de-activated when the VNA is Preset or when an Instrument State is recalled. This behavior can be changed with a Preference setting so that it remains active through a Preset or Instrument State recall.

  • PMAR configuration is NOT saved in an Instrument State file. Therefore, recalling a state file that refers to a device that has been removed, or recalling a state file on a different VNA will result in a “Device configuration not found” error.

External Devices  

The devices that are currently configured appear in this list. The number of devices that can be configured is limited by the specified Interface.

New  Click to create a new PMAR configuration. The default name is Device<n>, where <n> is the next number for 'Device'.

Remove  Click to remove the selected device from the list.

Properties

Name  Enter a device name as it will appear when referring to this device in all VNA dialog boxes. Edit the name at any time. Duplicate names are not allowed.

Notes

  • Because External Devices can be used with FOM ranges, do NOT name an external device any of the following FOM range names: “primary”, “receivers”, or “source”, “source1”, source2” and so forth. Learn more about FOM ranges.

  • Do NOT use a parameter name, such as "S11, or "R1".

Device Type  Select Power Meter.

Driver  Use AGPM for all Keysight Power Meters. See Supported Power Meters

Active  Check to make the device available for use in the FOM, New Trace, and Receiver Leveling dialogs. An instrument state that is saved with an Active device (checked) will include the device in the state file. Otherwise, if the Active box is cleared, the device will NOT appear in the state file.

Note: Multiple PMAR configurations for the same physical device can be Active and Enabled.

Device Properties  Click to launch the Configure Power Sensor dialog.

IO Configuration

Interface  Select the interface that is used to connect the device to the VNA. These devices will then appear in the 'Available' field. Choose from:

Available  Shows a list of devices that are connected to the specified IO Interface.

Refresh Click to rescan the specified interface for devices.

Selected  Enter the IO configuration or select from the available list of IO Interfaces found.

Enable I/O  Clear this box to disable communication with the selected device. You would do this to configure a device that is not yet connected to the VNA.

  • Communication with devices is attempted when Enable I/O is checked, Active is checked, and OK is pressed.

  • If communication with a device is lost, the affected channels are put into Hold.

  • When communication is attempted, devices with Enable I/O checked are queried for limits for frequency, power, and number of points. If there are limit problems, the VNA sends an error and the affected channels are put into Hold. These limits are enforced by the dialog box in which they are set. Resolve the reported limit problem and then restore the triggering.

  • Communication is also attempted when clicking the Settings button on the Configure Power Sensor dialog. You can not change any of the sensor settings unless Enable I/O and Active are checked and communication is possible with the sensor.

Configure Alias and LAN Devices

Use this procedure to configure a device using a LAN interface. Also use for ANY device for which you want to set an alias (easily-recognized) name. The alias name appears in the Available field when Aliases is selected as the Interface.

  1. On the VNA, minimize the VNA application.

  2. In the system tray (lower-right corner) right-click the IO icon, then click Keysight Connection Expert

To Add a LAN Device:

  1. In Keysight Connection Expert, click Manual Configuration tab.

  2. Select LAN Instrument.

  3. Click, then enter the IP address of the external source.

  4. Click Test This VISA Address to verify communication.

  5. Click Accept.

To create an Alias for a connected device:

  1. In the list of connected instruments, click the instrument, then click Add or Change Aliases.

  2. Enter the Alias Name to be used in the External Device Configuration dialog.

 

Power Sensor Configuration dialog box help  

To launch this dialog, with the PMAR device selected in the External Device Configuration dialog, click Device Properties .

This dialog is used to configure a power meter / sensor for use as a receiver.

To configure a single power meter for a Source Power Cal, use the Power Meter Settings dialog.

About Power Sensor Calibration

PMAR traces are NOT calibrated using standard VNA calibrations, including response corrections.

PMAR traces are calibrated using methods that are appropriate for the selected sensor. Follow the proper guidelines for zeroing or calibrating the sensors that are in use. Check to ensure that the selected sensor is appropriate for the frequency range and the power level at which PMAR measurements occur.

The VNA does not automatically prompt you to perform a calibration.

To calibrate a power sensor, click Settings on this dialog box, then click Zero/Calibrate Sensor. Learn more.

 

Note: By default, a PMAR is de-activated when the VNA is Preset or when a Instrument State is recalled. This behavior can be changed with a Preference setting.

Sensor

For power sensors that are connected to a power meter, select a sensor to configure.

Settings  Click to launch the Power Sensor Settings dialog.

When pressed, communication with the sensor is tested. Sensor settings can NOT occur unless Enable I/O is checked on the External Device Configuration dialog, and the sensor is properly connected and configured.

Sensor Settling

Each power meter reading is "settled" when either:

  • two consecutive meter readings are within this Tolerance value or

  • when the Max Number of Readings has been met.

The readings that were taken are averaged together to become the "settled" reading.

Tolerance  When consecutive power meter readings are within this value of each other, then the reading is considered settled.

Max Number of Readings  Sets the maximum number of readings the power meter will take to achieve settling.

Sensor Loss Compensation

Use Loss Table  Select this checkbox to apply loss data to Source Power calibration correction (such as for an adapter on the power sensor).

Edit Table  Invokes the Power Loss Compensation dialog box.

 

 

Power Sensor Settings dialog box help

This dialog appears when you click the Settings button on the Configure Power Sensor dialog.

Note: Be sure that the frequency range of your power sensor covers the frequency range of your measurement. This does NOT occur automatically.

Sensor A (B)  Displays one of the following messages depending on type of sensor.

  • Not connected  The VNA is not detecting a power sensor.

  • Sensor Data  Allows the following entries for power sensor data:

    • Reference Cal Factor  Specifies the Cal Factor for the 50 MHz reference signal.

    • Cal Factor Table  Specifies the frequency and corresponding Cal Factor for the sensor.  

    • Delete Cal Factor  Deletes the indicated row in the table.

    • Delete All  Deletes all data in the table.

    • To Add a Row to the table, click on a row in the table and press the down arrow on either the VNA front panel or keyboard. A row is added to the bottom of the table. The table is automatically sorted by frequency when OK is pressed.

  • Cal factors are contained within this sensor  Internal Reference Cal Factor and Cal Factor data are loaded automatically and the following dialog appears.

    • Use Internal Cal Factors  This box only appears when  internal cal factors have been detected for the sensor and by default will be checked. Clear this box to not use internal cal factors.

Load Cal Factors  Click to load cal factors from a *.csv file that you create from the cal factors that appear on the sensor. The first line of the file MUST have the reference Cal Factor (typically 100), followed by Freq / Cal Factor pairs as show in the following image:

Save Cal Factors  Click to save the cal factor table to a *csv file.

Limit Frequency Range  

  • Check to limit the use of the power sensor to those within the Minimum and Maximum frequency values.

  • Clear to use the power sensor for all measurements. If the measurement frequency is not within the Minimum and Maximum frequency values, the closest min or max correction data is used for the measurement.

Minimum Frequency  Specifies the minimum frequency range for the sensor.

Maximum Frequency  Specifies the maximum frequency range for the sensor.

Zero and Calibrate the Power Sensor

For highest accuracy, Zero AND Calibrate the power sensor before measuring data. Follow prompts that may appear.

Zero - If the following settings are 'greyed', Internal or External zeroing is selected automatically based on the power meter/sensor model. Otherwise, select the appropriate type of zeroing to perform, then press Zero.

  • Internal Zero - A switch inside the power sensor removes the sensor from the incident power.

  • External Zero - Requires that you physically remove the sensor from incident power.

Note for the U2000 Series USB power sensors

Calibration is NOT available. Select External Zero ONLY when the power to be measured is below the specified level. Otherwise, the U2000 series performs internal zeroing automatically when needed. See your power sensor documentation for more details.

  • U200xA - below -30 dBm

  • U200xH - below -20 dBm

  • U200xB - below 0 dBm

If your U2000 power sensor 'hangs' when external zeroing, upgrade the power sensor firmware to Rev. A.01.02.00 or higher to fix this problem.

Calibrate - Available when the selected sensor has calibration capability. Calibration involves measuring an internal 1 mW source.

  • Keysight P-Series sensors have an internal reference so you can calibrate them without connecting to the meter’s reference port.

  • Keysight U2000 USB power sensors do not require calibrating.

  • For other sensors, refer to the documentation to determine if it has calibration capability.

Press Calibrate, then follow the prompts.

 

Power Loss Compensation dialog box help

To Add a Row to the table, click on a row in the table and press the down arrow on either the VNA front panel or keyboard.

To Edit a value, double-click in the cell to be edited.

Compensates for losses that occur when using an adapter or coupler to connect the power sensor to the measurement port. These components will be removed when the calibration is complete. To account for components that will remain during the measurement, use the Power Offset setting.

The Frequency / Loss pairs define the amount of loss for the entire frequency range. For example, using the entries in the above dialog image:

  • 0.5 dB is used to compensate power sensor measurements up to 1 GHz.

  • Each data point between 1 GHz to 2 GHz is linearly interpolated between 0.5 dB and 1 dB.

  • 1 dB is used above 2 GHz.

  • A single frequency/loss segment is applied to the entire frequency range.

Beginning with A.09.80, enter up to 9999 segments to achieve greater accuracy. Previously the limit was 100.

Note: Large segment counts with one or more power sensors can result in long load and close times for the VNA Application.

 

Frequency  Enter a frequency in Hz.

Loss  Enter a loss as a POSITIVE value in dB.  To compensate for gain, use NEGATIVE values.

Delete Table Segment  Deletes row indicated in the field.

Delete All  Deletes all data in the table.

The Power Loss Compensation table survives VNA Preset and Power OFF. To NOT use Loss compensation, clear the Use Loss table checkbox on the Configure Power Sensor dialog.

Use a PMAR Device to confirm a Source Power Cal

Learn how to create and configure PMAR device.

After a Source Power Cal has been performed, use the same sensor as a configured PMAR to analyze the accuracy of the Calibration.

  1. Create a PMAR device with the power sensor that will be used for the Source Power Cal.

  2. Perform a Source Power Cal. Learn how.

  3. Create an unratioed measurement with the PMAR device. Learn how.

  4. With the power sensor still connected to the test port, monitor the corrected source power using Min and Max markers or the Trace Statistics peak-to-peak feature.