Integrated Pulse Measurements

How to start the Pulse Setup dialog

To provide quicker access, use the Setup softkey. Learn how.  

Hardkey/SoftTab/Softkey

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

Pulse Setup dialog box help

The Basic (upper box) controls allow simple pulse measurements using the default (Autoselect) settings in the Advanced section (lower box) of the dialog.

Pulsed measurements are performed in a Standard channel. See Measurement Class. However, several VNA measurement settings are controlled by the Pulse setup, such as sweep type, number of points, and so forth.

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 Profile - Pulse profile measurements provides 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.

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.

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

Pulse Timing

Pulse Width - Sets the width of the source pulse. See measurement timing to learn how to control the receiver width and delay.

Pulse Period  The time to make one complete pulse.

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

By default, these settings configure Pulse Gen 1 to drive Source Modulators 1. This can be changed from the Advanced Settings Pulse Generator Setup dialog.

-------- Advanced Settings ----------

The following settings allow maximum control of a Pulse measurement.

Properties

Autoselect pulse detection method - check to automatically switch between Narrowband and Wideband based on the Pulse Width.

In Standard Pulse:

• Wideband - used when the (source) Pulse Width is WIDER than the fastest receiver acquisition time.  This allows the receiver to measure all pulse ON time - no pulse OFF time.  The VNA will select Wideband whenever possible. (Only Wide band is available for M9485A)

Autoselect IF Path Gain and Loss - For future use.

Optimize Pulse Frequency - Automatically selects the Pulse Frequency and Pulse Period. (This is not available for M9485A)

Autoselect Profile Sweep Time - In Pulse Profile mode, adjusts the default X-axis start time to zero and the stop time double the Pulse Width. This allows you to see one complete pulse. If unchecked, the Sweep Time will not be changed.

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IFBW - Select the IFBW for the measurement.

• this setting determines the receiver acquisition time - approximately 1/ IFBW.

Measurement Timing

Source1 - Used as RF Source Modulation Drive.

• Width - source pulse width.

• Delay - source pulse delay relative to the pulse generator clock.

• Pulse Gen - Pulse generator used to modulate the source. Select CW to have NO source modulation.

• all receiver paths are the same.

Master Pulse Trigger  Choose from:

• Internal - Default setting. Pulse0 generator is used to trigger the ADC to make pulse measurements.

• External - External pulse input from PULSE SYNC IN is used for pulse trigger.

• <External Pulse Gen name> - Available when a 81110A is configured as an External Device and Master Mode is checked on the pulse generator properties dialog.  See how to make this setting using SCPI .  

Autoselect Width and Delay - When checked, for Wideband mode and Pulse0, the default setting for the receiver is adjusted to approximately 75% of the source pulse width, with 20% delay. This leaves approximately 5% of the source pulse ON after acquisition is complete. This pulse width is further adjusted after an IFBW is selected.

Autoselect Pulse Generators - When checked:

• Pulse1 is selected for Modulator Drive.

• Pulse0 is selected to gate the ADC.

Pulse Generators  Click to launch the Pulse Generators Setup dialog.

Pulse Generators Setup dialog box help

This dialog is available with Option 025.

To see this dialog, press Pulse Gen Setup on the Pulse Setup dialog.

Pulse Generators

Configure the Pulse Generators to be used for your measurement.

When configured, external pulse generators appear in this list. Learn more.

Pulse0 triggers the VNA receivers when Enabled. The Width can NOT be configured. Delay defines the delay between the pulse clock and when the receiver begins to make a measurement. Learn more.

• 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. P-(D+W) >120 ns should be satisfied.

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  Choose from: (When ONE of these is changed, they ALL change. The internal Pulse Generators can NOT be triggered individually).

• Internal - Pulse generators are triggered by the internal pulse clock.

• External - Pulse generators are triggered by an external pulse generator.

Frequency - Set the pulse frequency of each generator.

• Pulse Frequency (PRF) = 1 / Period

• P = Period; one complete pulse cycle

Learn more about the Pulse Generators.

Pulsed Source

Check to enable one or both internal source modulators.

Important: When internally modulating the sources, source leveling is automatically set to Open-loop.

Modulator Drive  Choose the pulse generator to modulate the specified source. Choose from CW (NO pulse), Pulse 1, 2, 3, 4, External.  

Pulsed Receivers

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 can NOT be configured.

ADC trigger delay - Set the amount of time to wait before triggering the ADC to begin acquisition. This is the same as Pulse0 Delay.

Use Pulse4 output connector to indicate ADC activity - Check to use an oscilloscope connected to Pulse4 pin to display when the ADC is making measurements.

Pulse Trigger.. Click to start the Pulse Trigger dialog.

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.

Pulse Sync 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 period is ignored and the internal pulse generator puts out one set of pulses (P0-P4) per external trigger. All five pulse outputs have unique delay and pulse width settings.

The PULSE SYNC IN pin provides a configurable trigger signal into the Pulse Generators. Only one set of pulses is emitted when edge triggering is used. The length of time that it takes to emit one set of pulses is the end time of the last enabled pulse (largest of width + delay of all the pulses P0-P4).

Level/Edge

Sets the edge or level of the trigger signal to which the internal pulse generators will respond when being externally triggered at the PULSE SYNC IN 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.

19-Dec-2013

Added Pulse-to-Pulse

11-Apr-2010

MX New topic (A.09.20)