Integrated Pulse Measurements

How to start the Pulse Setup dialog

Using Hardkey/SoftTab/Softkey

Using a mouse

1. Press Sweep > Source Control >  Pulse Setup....

1. Click Stimulus

2. Select Sweep

3. Select Sweep Control

4. Select Pulse Setup...

Pulse Setup dialog box help

The appearance of this dialog changes slightly between two pulse measurement types: Standard Pulse and Pulse Profile, as shown below. Additionally, the dialog can be switched between Basic and Advanced modes.

The dialog comprises four groups of properties for pulse configuration:

• Pulse Measurement

• Pulse Timing

• Properties

• Measurement Timing

Standard Pulse (ENA)

Pulse Profile (ENA)

Basic and Advanced Modes

Basic mode settings appear when you first open the dialog. Clicking the Advanced >> toggle button expands the dialog to access additional pulse settings. Click Basic << to hide the advanced settings.

Basic mode controls simple pulse measurements, using the default (auto-selected) settings in the Advanced section of the dialog.

Advanced mode accesses the additional settings, providing you maximum control of a pulse measurement configuration.

Pulsed Profile measurements are performed in a Standard channel. (See Measurement Class.) Standard Pulse measurements are supported by most channel types.

Several VNA measurement settings are controlled by Pulse Setup, such as sweep type, number of points, and so forth..

Pulse Measurement

Enable Pulse (checkbox)

When enabled, the source and receivers are pulsed. The default state is disabled (not checkmarked). The Standard Pulse and Pulse Profile radio buttons remain selectable in either state.

Standard Pulse (radio button)

This measurement type is selected by default. With pulsed RF, the VNA can be configured to sweep in frequency, power sweep, and CW time. This measurement type is used for Point-in-Pulse measurements and Pulse-to-Pulse measurements.

Pulse Profile (radio button)

Pulse profile measurements provide a time-domain (CW frequency) 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. (This function is available in standard class only.)

Pulse Profile measurement using default settings and R1 receiver.

• Pulse Profiling can be performed using ratioed or unratioed measurements. You can preview the pulse on port 1 by using an R1 receiver measurement.

• Pulse Profiling is performed at a single CW frequency in Wideband mode.

• To select the CW Frequency, click Stimulus, then Sweep Type.

• In Wideband mode, the receiver is walked across the pulse by making a sequence of closely-spaced measurements in real-time.

Pulse Timing

Pulse Width

Defines the width of the RF pulse. See measurement timing to learn how to control the receiver width and delay.

In Advanced mode (expanded), the label "Pulse Width" will include an asterisk *. This value is linked to the pulse width of the modulating source, which will also be indicated with an asterisk * in the timing table.

Pulse Period

Defines the period (i.e. one complete pulse) of the pulse train.

Pulse Frequency (PFR)

The reciprocal of Period (1/ Period). See Internal Pulse Generators to learn more.

Properties

Detection

This function is not available. Only Wideband is available in E5080B, E5081A.

For Standard Pulse:

The VNA will select Wideband any time the RF pulse width is longer than the shortest receiver acquisition time, which is approximately the reciprocal of the widest available IFBW with some added margin.

For Pulse Profile:

The VNA will select Wideband any time the RF pulse width is longer than the shortest receiver acquisition time multiplied by 6, which is approximately the reciprocal of the widest available IFBW multiplied by 6.

IF Path

Auto is Enabled by default. To manually change the IF Path settings, uncheck the Auto checkbox and click the "IF Path..." button to open the IF Path dialog.

IFBW

Auto is Enabled by default.

When Auto is enabled in Standard Pulse mode:

• For Wideband detection mode the IFBW with the longest acquisition time that fits within the specified RF pulse width, with some margin, is selected.

When Auto is enabled in Profile Pulse mode:

• For Wideband detection mode an IFBW is selected based on RF pulse width. VNA chooses an IFBW whose acquisition time results in a profile sweep with a point count around 201.

Point Count

Displays the read-only point count that will be set when the settings are applied.

X-Axis Start/Stop

This property is only available in Pulse Profile mode.

Auto is Enabled by default.

If Auto is selected, the VNA will automatically change the X-axis start and stop times so that the profile is centered on the screen and occupies 50% of the screen.

If Auto is not selected, the start and stop times may be manually specified.

Note: The X-Axis timing values are affected by the "Rcvr ADC Delay" and "Nominal RF Mod Delay" values.

Measurement Timing

Table Properties

Source (Rows)

These rows control the modulators associated with each source or source port. Source rows whose names contain an asterisk * have width values that are coupled to the Pulse Width property in the Pulse Timing panel.

Recv (Rows)

In Wideband detection mode these rows control the receiver timing. The receivers can only be driven by Pulse0.

Width and Delay (Columns)

Auto is enabled by default.

When Auto is enabled, the widths and delays will be automatically chosen by the VNA.

In Standard Pulse mode:

• For the Wideband detection mode, the receiver width represents the acquisition time of an automatically chosen IFBW. The IFBW with the longest acquisition time that fits within the specified RF pulse width, with some margin, is selected. The receiver delay is chosen to align the receiver trigger (Pulse0) with the RF pulse, accounting for the specified RF delay.

To manually change the widths or delays, uncheck the Auto checkbox to enable the cells in these columns.

Pulse Gen (Column)

Auto is enabled by default.

While Auto is enabled the VNA will select Pulse1 to drive all source modulators and Pulse2 to drive all IF gates.

To manually specify which pulse generator drives each row, uncheck the Auto checkbox to enable the cells of this column.

In addition to the internal pulse generators, other pulse generator selections are available:

• CW – Drives the row with a continuous ‘High’ signal.

• External – Drives the row with an external generator being defined in the External Device dialog. For “Source” rows the signal provided to the “RF Pulse Mod In” IO is used. For “Recv” rows the signal provided to the “IF Gate A In”, “IF Gate B In”, “IF Gate C In”, and “IF Gate D In” are used to drive the corresponding IF gate.

• Other external generators that have been defined in the External Device dialog.

Trigger

Note: This provides the same selections as provided in the Pulse Generators Setup dialog and the Trigger dialog on its "Pulse Trigger" tab.

Offset Pulse Delays Using (checkbox)

This checkbox is also found in the Pulse Generators Setup dialog.

Modulator Delay

ADC Delay

Pulse Generators... (button)

This button is only available if Pulse is enabled.

Opens the Pulse Generators Setup dialog.

Plot Pulse Timing... (button)

Pulse Setup (Modulation Distortion Channel) dialog box help

Note: The E5080B does not support this function.

Pulse Measurement

Off - Source and Receivers are NOT pulsed

Standard Pulse - With pulsed RF, the VNA can be configured to sweep in frequency, power sweep, and CW time.

Pulse Timing

RF Pulse Width - Sets the width of the RF Source pulse.

Pulse Period (menu) - Allows the selection of the following:

• Pulse Period - The time to make one complete pulse.

• Pulse Frequency - The reciprocal of Period (1/ Period).

• Pulse Duty Cycle - Pulse Width divided by the Pulse Period.

Labels:

• Sweep - Complete cycle time of measurement including background sweeps.

• Acquire - The ADC acquisition time required to measure the data for a single FFT.

• Pulse/Swp - Number of pulses which will occur during the sweep, including pulses used for background sweeps.

Pulse Details

Generator - Pulse generator outputs in numerical order.

Device -  Indicates the device being controlled by the pulse generator output.

• Pulse0 - Always set to Receiver. Sets the amount of time to wait before triggering the ADC to begin acquisition and is always selected for Pulse0 and cannot be changed. Pulse0 adds (ADC Delay) + (Modulator Delay). The ADC will begin measuring data 250 ns before the rising edge of Pulse0. This delay is indicated in the Fixed ADC Delay = 250 ns annotation.

• Pulse1 through Pulse4 - Pulse outputs can be set to the following:

  • RF - Selecting RF indicates that the pulse signal is used to drive the RF modulator. Only one pulse generator output can be used to drive an RF source. If you try to set more than one pulse generator output to RF, then the other one will be set to User N (where "N" is the pulse generator number).

  • User 1, User 2, User 3, User 4 - Labels for user convenience. These labels do not connect the pulse generator to any specific hardware. These selections may be used to control a DUT, DC biases, or other signals.

  • Pulse4 ADC Activity - (Pulse4 only) Pulse4 can also be set to ADC. This selection outputs a signal on Pulse4 when the ADC is active. This is the same as Pulse4 Output Indicates ADC Activity on the Pulse Generators Setup dialog. If ADC is selected for Pulse4, then the pulse width and delay entries are grayed out because Pulse4 is no longer a pulse output.

Width - RF Source pulse width. This setting is the same as Pulse Width under RF Pulse.

Delay - If the Offset Pulses using ADC Delay check box is disabled, then the delays are the pulse delays relative to the trigger. If the Offset Pulses using ADC Delay check box is enabled, then the delays are defined for the pulses relative to each other. In this case, you can enter negative delays, and the delay from the trigger will be adjusted to correct for these values.

Invert - Check to cause the pulse ON time to be active low and OFF be active high.

Enable  Check to enable individual pulse generators.

Autoselect Receiver Timing - Computes the width to 80% of the RF Source Width and the delay will be 10% of the RF Source Width. With this setting selected, the Width and Delay columns in the table are grayed out.

Offset Pulses using ADC Delay Check Box

• If checked (default), adds delays to the Pulse Generator:

  • Pulse0 adds (ADC Delay) + (Modulator Delay).

  • Pulse Output used as the Modulator Drive adds no delay.

  • All other Pulse Outputs add Modulator Delay.

• RF Modulator Delay

  • Defines the RF delay of the source modulator. This is the time lag between the pulse drive signal and the actual RF output. This may indicate the lag for either an internal or external source. The default is 40 ns.

• ADC Delay

  • Represents the delay caused by internal data processing. This value cannot be changed.

Timing Example

Assume Pulse1 is used to modulate the RF signal, all Pulse outputs are enabled, all are set to zero delay, and all are set to the same width. The first timing diagram below is with offset off and the second timing diagram is with offset on.

Pulse Generators... (button)

This button is only available if Pulse is enabled.

Opens the Pulse Generators Setup dialog.

Plot Pulse Timing... (button)

Pulse Generators Setup dialog box help

Pulse Generators Setup Dialog (ENA)

This dialog is available with Option S9x025A/B and S9x024B (pulse generators).

To see this dialog, click Pulse Generators... in the Pulse Setup dialog.

Pulse Generators (table)

Configure the Pulse Generators to be used for your measurement. The pulse 0 is for the receiver. The pulse 1 is for source and P1 output and pulse 2 to 4 are for P2 to P4 output signal, respectively.

• D = Delay; the time before each pulse begins

• W = Width; the time the pulse is ON

• Duty Cycle = W/P

• P = Period; one complete pulse cycle

• Pulse Frequency (PRF) = 1 / Period

Important: If D + W is greater than P, then undefined VNA behavior results. There is NO error message or warning.

Learn more about the Pulse Generators.

Invert

Check to cause the pulse ON time to be active low and OFF be active high.

Enable

Check to enable individual pulse generators.

Trigger (combo box)

All trigger fields are coupled. Changing one changes all. The internal Pulse Generators can NOT be triggered individually.

This provides the same selections as provided in the Pulse Setup dialog and the Trigger dialog on its "Pulse Trigger" tab.

Frequency

Set the pulse frequency of all pulse generators.

• Pulse Frequency (PRF) = 1 / Period

• P = Period; one complete pulse cycle

Period

Set the period of all pulse generators.

Pulsed Sources (table)

(E5080B) The pulsed source is available with pulse modulation hardware option (021).

Check to enable the required internal source ports.

Shows either two or four sources depending on the hardware.

The source row labels, are not affected by the simultaneous Source license.

Enable (checkbox)

Enables source modulation.

Disabled by default.

The Enable checkboxes are not affected by the simultaneous Source license.

Modulation (combo box)

Choose the pulse generator to modulate the specified source. Choose from CW (no pulse), Pulse 1, 2, 3, 4 and so on..., External.

If the VNA option does not allow pulse on a given source, then it is grayed-out.

The Modulation choices are not affected by the simultaneous Source license.

Properties

Synchronize ADCs using Pulse Trigger

Check to enable triggering used to gate the ADC for wideband receiver measurements. This is the same as Pulse0 Enable

The Width cannot be configured.

Pulse4 Output Indicates

Check to use an oscilloscope connected to the pulse 4 (pin 13 of the PULSE I/O connector on the rear panel of the VNA) to display when the ADC is making measurements. There are two selections:

• All ADC Activity - When selected, all ADC activity can be monitored, including ADC activity that may not be displayed on a trace. An example is background measurements that are used for receiver leveling, but are not actually displayed on a trace.

• Trace ADC Activity - When selected, Pulse4 will be active only during measurements that will be displayed on a trace.

Offset Pulse Delays Using (checkbox)

This checkbox is also found in the Pulse Setup dialog.

Modulator Delay

ADC Delay

Offset Pulse Example

Assume Pulse1 is used to modulate the RF signal, all Pulse outputs are enabled, all are set to zero delay, and all are set to the same width. The first timing diagram below is with offsets off and the second timing diagram is with offsets on.

Trigger... (button)

Accesses the Trigger dialog on the Pulse Trigger tab.

Plot Pulse... (button)

Pulse Trigger Tab - Trigger dialog box help

To see this dialog, press Pulse Trigger on the Pulse Generator Setup dialog or select Stimulus, then Trigger from the VNA Menu.

Trigger Source

Select Internal or External to provide sync capability for the internal pulse generators.

• Internal - The pulse generator is internally triggered and puts out a periodic pulse train with a period defined by the Pulse Generator Setup dialog.

• External - The internal pulse generator puts out one set of pulses (P0-P4) per external trigger (Pulse Sync In). All five pulse outputs have unique delay and pulse width settings.

Trigger Level/Edge

Sets the edge of the trigger signal to which the internal pulse generators will respond when being externally triggered at the PulseSyncIn pin..

Positive = rising edge; Negative = falling edge.

Receiver synchronization

Synchronize ADCs using pulse trigger - Check to enable triggering used to gate the ADC for wideband receiver measurements. The Width can NOT be configured.

ADC trigger delay - Set the amount of time to wait before triggering the ADC to begin acquisition.