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Narrowband Pulsed Application

Note: Beginning with the A.14.80.xx firmware release, the Narrowband Pulsed Application is no longer available. The Integrated Pulse App (Opt S93026A/B) replaces this application.

The Narrowband Pulsed Application is a Visual Basic program that provides a user interface for making pulsed measurements.

In this topic:

See Also

Other IF Access Topics

Required Options and Equipment

The VNA H08 option provides the Narrowband Pulsed Application. The following options are also required. If your VNA does not have the required options, a message is displayed on the screen. For more information, see Pulsed-RF Measurements Configuration Guide

Models

Other VNA Models

Connecting External Pulse Generators to the Z5623A H81

Each 81110A Pulse Generator has two output modules. Each output can drive a VNA IF Receiver or Source Modulation (Z5623A H81).  Connect the Pulse Generators as follows:

81110A front panel connectors

Connect the Z5623A H81Pulse Test Set (optional) to the VNA front-panel port 1 loops as follows:

VNA

H81

Src Out

Source IN

CPLR THRU

CPLR THRU

RCVR R1 IN

RCVR R1 Out

See Also

Using the Narrowband Pulsed Application

How to start the Narrowband Pulsed Application

Using Hardkey/SoftTab/Softkey

Using a mouse

  1. Press Macro > Pulse

  1. Click Utility

  2. Select Macro

  3. Select Pulse

See Also

Keypad Data Entry

The VNA front-panel Numeric Entry and Navigation keys can be used for dialog box input. Also, a keyboard can be used to enter values, including alpha characters for prefixes (for example, u for usec.) . After typing values, first press Enter, then press Tab to go to the next field.

The following is an image of the main dialog box:

Pulsed Application Main dialog box help

Note: An error message may appear on the VNA stating that the response frequency has exceeded the maximum allowed frequency.

The Narrowband Pulsed Application may set the offset frequency (option S93080A) of the VNA to some value other than zero (the default value). If the stop frequency is set to the maximum of the VNA model, then the error message will appear.

To fix this, set the stop frequency to a value that is at least 2 kHz less than the maximum allowed. For example, if you have a 20 GHz VNA, and the stop frequency is set to 20 GHz, and the error message appears, then set the stop frequency to 19.999998 GHz

See Block Diagram of IF Path / Pulse Generators / Source Modulation

Configure

You can configure more than one channel to make pulsed measurements, but the channels must use the same pulse generator settings.

Only the Keysight 81110A Pulse Generator is supported with the Narrowband Pulsed Application. Refer to the 81110A documentation for pulse repetition frequency and duty cycle capabilities.

See Also

Edit / Undo  Pulse Application settings revert to those when Apply was last pressed.

Desired PRF and IFBW   Enter the DESIRED values. When Calculate is pressed, one or both of these values may change.

Pulse Repetition Frequency (PRF): Frequency of the pulses from the Pulse Generator.

Pulse Repetition Interval: 1/ PRF  Changes to either PRF or this setting changes both.

Receiver IF Bandwidth: IF Bandwidth of the VNA. Choose a setting from 1 Hz to 10 KHz.

Fixed PRF  When checked, (default setting) the Calculate algorithm will NOT adjust the PRF, but only change the IF Bandwidth. When cleared, both the PRF and IF Bandwidth values are adjusted as necessary.

Note: On VNA's with DSP version 4, the Calculate algorithm will NOT find nulling at several PRF frequencies. If this error is returned, add a small offset to the PRF (for example, 2.1 MHz instead of 2 MHz) or clear the Fixed PRF checkbox.

Modulation/Gates   The Source Modulation and four VNA receiver gates can each have their own, or share, Pulse Generator outputs. Shared outputs have identical Width and Delay values.  To configure and enable outputs, click Configure, then Pulse Generators to launch the Pulsed Generator Configuration dialog box.

Note: Option 036 and 037 limits the Source Modulation width to 117 ns.

Width  Pulse Width.

Delay  The delay that occurs before the pulse.

 

Duty Cycle  Calculated Duty Cycle of the source and each of the selected receivers. Updated when Calculate is pressed.

Pulse Mode On  When this box is checked, the VNA is enabled for Pulsed measurements. The VNA Status Bar annotation indicates the following:

  • G  Internal IF gates enabled.

  • F  Filtering for Pulsed Measurements enabled.

Apply  All selections are sent to the pulse generator and the active channel of the VNA.

Calculate  All selections are calculated and valid PRF and IFBW values are entered in their fields. If these settings are not acceptable, try changing the values you previously entered and click Calculate again. When acceptable values are attained, click Apply to send these values to the pulse generator and VNA.

Pulse Profile  Launches the Pulse Profile dialog box. Same as clicking View / Pulse Profile. If not available, check Pulse Mode ON, click Calculate, then Apply.

Minimize  Click to minimize the dialog box to make changes in the VNA application. To see the dialog again, select Macro, Pulse, or turn the Status Bar ON.

Save  All settings from the Narrowband Pulsed Application are saved in a *.ppf file. These settings are NOT saved with VNA instrument state.

Recall  Restore settings from the specified *.ppf file that were previously saved.

Close  Closes the dialog box without saving changes.

 

How to configure Pulse Generators / Modulators and Receivers

From the Pulse App main dialog box

Learn about...

  • Configure Receiver Gain

  • Converter Measurements

  • No Pulse Generators  When checked, the Narrowband Pulsed Application does NOT attempt to communicate with internal or external pulse generators. This setting is used for troubleshooting purposes.

  • No SW Gating  When checked, the improved SW gating sensitivity is turned OFF. This setting is used for troubleshooting purposes.

 

Pulsed Generator Configuration dialog box help

Notes:

Configures either the internal pulse generators (PNA-X models with relevant options), or Keysight 81110A Pulse Generator outputs.  You can configure each 81110A Pulse Generator with either one or two 81111A output modules.

The Source Mod and four VNA receiver gates can each have their own, or shared, pulsed generators allowing identical Width and Delay values which are selected on the Main dialog.

To share an external generator output between one or more VNA inputs, use the same GPIB address and output module for each VNA input.

Internal Pulse Gen Output (available ONLY on the PNA-X opt S93025A/B)

Specify the Pulse Gen (1 through 4) to use to modulate each of the VNA receiver IF gates or Sources.

External Pulse Generator settings

GPIB Addr: The GPIB address of the 81110A.

Output: The output module of the 81110A.

Primary: The 81110A that uses the 10 MHz reference signal from the VNA.

Enabled: Turns the pulse output ON.

External Gate/Modulator settings

High: Specify a 'TTL-High' voltage level

Low: Specify a 'TTL-Low' voltage level

Ext Impedance: Impedance of the modulator used to create the pulse.

Complement: When this box is cleared, TTL HIGH is the pulse. When checked, TTL LOW is the pulse.

Using Internal Modulators  When this box is checked, the voltage, impedance, and complement values are forced to settings that prevent damage to the internal modulator.

Using Internal Pulse Generators  Makes the appropriate settings on this dialog available.

Using Internal VNA gates  When this box is checked, the voltage, impedance, and complement values are forced to settings that prevent damage to the internal gates.

 

Receiver Gain Configuration dialog box help

See Block Diagram of PNA-X IF Path / Pulse Generators / Source Modulation

This dialog may look different depending on the VNA model and number of receivers available.

Sets the gain of each VNA receiver manually or automatically.

Auto  - The VNA selects the best gain level to make pulsed measurements.

Use the following to manually set the gain for each receiver.

Low - about 0 dB of gain

Medium - about 17 dB of gain

High - about 24 dB of gain  

The PNA-X has the following attenuation settings:

Low - 30 dB of attenuation

Medium - 15 dB of attenuation

Hi - 0 dB of attenuation

Calibration in Pulse Mode

To perform a calibration in pulse mode (option H08), first configure and apply the pulse parameters (PRF, Pulse Width, Delays, IF gating, and so forth) before calibrating the system. This will ensure the VNA is configured properly during the calibration and measurement.

When performing Unknown Thru or TRL calibrations, ALL receivers must be gated. Otherwise, the error terms will not be correct after the calibration has completed. This can be accomplished by either having a separate pulse generator output for each of the IF gates, or by connecting pairs of the IF gates together with BNC-T's.  For example, if the pulse generator does not have enough outputs, then connect the R1 and R2 IF gates to the same pulse generator output. Also, connect the A and B IF gates to either separate outputs (recommended) or one output (reduces flexibility). The error terms will then be valid after the calibration is complete.

Pulse Profiling

Pulse profiling provides a time domain view of the pulse envelope. Profiling is performed using a measurement technique that "walks" a narrow receiver "snapshot" across the width of the pulse. This is analogous to using a camera to take many small snapshots of a wide image, then piecing them together to form a single, panoramic view.

How to perform Pulse Profiling

From the Pulse App main dialog box,

Click the Pulse Profile button. or:

If this setting is unavailable, check Pulse Mode ON, click Calculate, then Apply.

 

Pulse Profile dialog box help

Learn about Pulse Profiling (scroll up)

See Block Diagram of PNA-X IF Path / Pulse Generators / Source Modulation

Modulation / Gates

These setting duplicate those found on the main Pulse App dialog box.

In Pulse Profile, the Gate Delay settings (highlighted in yellow) are significant only with certain Measurement Parameter and Couple Gates settings.

Time Parameters

Start, Stop  These two combine to make the window of the assembled pulse profile. To view the entire pulse, the start and stop values must be at least as wide as the Source Modulation Width plus Delay value.

Step  Each consecutive snapshot is incremented by this value until the stop value is reached. Therefore, the number of points for the pulse profile measurement can be calculated as: (Stop - Start) / Step. The higher the number of points, the longer it takes to make the measurement.

Measurement Parameter

CW Freq.  Frequency of the VNA source.

Source Port  The VNA port supplying the source power. Only required for single receiver (unratioed) measurements.

Param(eter)  Only those receiver gates (and relevant measurements) that are configured in Pulsed Generator Configuration are available.

Note: When a single receiver (unratioed) is selected, Gate Delay Settings (highlighted in yellow on above dialog image) are ignored.

If the reference receiver gate is NOT configured, the average of the Source Modulation pulse is used as the reference. For example: With S21 Selected, but ONLY B receiver gate is configured, then...

B Gate is walked across the Source Modulation pulse.

Source Modulation pulse average is used as reference (not gated).

 

Coupled Gates  Used when the appropriate receiver gates are configured for your S-parameter measurement ONLY. This setting is ignored when a single receiver (Param) is selected.

  • Uncoupled (box cleared)  The reference gate is FIXED at the delay setting as the test gate is walked across the Source Modulation pulse as dictated by the Time Parameter settings.

For example:

S21 Selected, B and R1 receiver gates configured, Gates Uncoupled

B Gate is walked across the Source Modulation pulse.

R1 gate is fixed at pulse width and delay setting.

  • Coupled (box checked)  The reference gate is walked synchronously with the test gate as dictated by the Time Parameter settings.  Only the difference between the test and reference gate delay values is significant; NOT the absolute values.

For example:

S21 Selected, B and R1 receiver gates configured, Gates Coupled

B gate delay = 3 microseconds,

R1 gate delay = 2 microseconds

Difference = 1 microsecond

B Gate is walked across the Source Modulation pulse.

R1 gate is  fixed at pulse width and delay setting.

B gate leads R1 gate by 1 microsecond.

 

Data Format  Log Magnitude,  Linear Magnitude, or Phase (only available if S-parameter selected).

Buttons

Show Gates  Allows you do change the receiver gating width and delay while looking at the results.

Apply Gate Settings  Click after making changes to gate settings.

Continuous Sweep  Check, then click Measure, to continuously measure pulse profiling.

Measure  Click to start the pulse profile measurement. Becomes Stop when continuously sweeping.

Marker to Delay  After making a measurement, you can drag the display maker to any point along the trace. Click this button and the marker time is entered into the Receiver Delay field on the main dialog box.

Save Data  Saves time domain data to the VNA hard drive in any of the following formats:

  • Touchstone (*.s1p)

  • Comma delimited (*.prn)

  • Citifile (*.cti)

Learn more about these data formats

Signal Reduction versus Gate Width

Signal Reduction versus Gate Width

PRF = 1 MHz

The following two figures show the performance of the internal IF gates as the width is narrowed.

The following is a zoomed image of the shaded area (above).

  • The straight line shows the theoretical loss in dynamic range due to duty cycle effects when using narrowband detection.  

  • The curved (red) line shows the actual measured performance of the gates.

  • The minimum gate width for <1dB deviation from theoretical is approximately 20ns.

See the specifications for the option H11 and option H08.

 

Pulsed Frequency Converter Measurements

The Narrowband Pulsed Application works with both FCA (option S93083A/B) and standard Frequency Offset (opt S93080A) measurements. On the Configure menu, check Converter Measurements. When checked, this setting prevents the Narrowband Pulsed Application from overwriting frequency offset values. This may limit the number of PRF and IFBW solutions that are returned when Calculate is pressed on the main Pulsed Application dialog box.

Note: Pulse Profiling can NOT be performed with frequency converter measurements.

Writing your own Narrowband Pulsed Application

You can use the Narrowband Pulsed Application or use an example program as a template for making your own Narrowband Pulsed Application.

The Narrowband Pulsed Application uses a custom .dll to perform the calculations that are necessary to make pulsed measurements. Use the COM Method below to send and return values to agilentPNApulsed.dll. Then use SCPI or COM commands to control the VNA.

COM Example Program

PNA-X Create

SCPI Example Programs

Point-in-Pulse

Pulse Profile

COM Methods

ConfigEnhancedNB2

ConfigEnhancedNBIFAtten

SCPI commands

SCPI

COM commands

COM

Install and Register the Pulsed .dll on your PC

To create your own Narrowband Pulsed Application, or run the Narrowband Pulsed Application from a remote PC, you must do the following:

  1. Copy the following files from the VNA  C:\program files(x86)\Keysight\network analyzer\  to a directory on your PC.

  2. To register the ActiveX DLL in Microsoft Windows Operating System:

For Operating Systems other than Windows, see their associated help files to learn how to register DLL files.