Trigger

A trigger is a signal that causes the VNA to make a measurement sweep. The VNA offers great flexibility in configuring the trigger function.

View the interactive Trigger Model animation to see how triggering works in the VNA.

See other 'Setup Measurements' topics

Trigger Setting

 How to set Triggering

Using Hardkey/SoftTab/Softkey

Using a mouse

  1. Press Trigger > Main > Trigger....

  1. Right click on the Trig or Meas icons on the status bar.

  2. Select on Trigger....

Note: The Continuous, Single, and Hold settings apply ONLY to the active channel. These settings are available from the Trigger menu, Active Entry keys, and softkeys

Trigger Setup Dialog Box Help

View the interactive Trigger Model animation to see how triggering works in the VNA.

Trigger Source

These settings determine where the trigger signals originate for all existing channels. A valid trigger signal can be generated only when the VNA is not sweeping.

Internal - Continuous trigger signals are sent by the VNA as soon as the previous measurement is complete.

Manual - One trigger signal is sent when invoked by the Trigger button, the active toolbar or a programming command.

External (uses MEAS TRIG IN) - Trigger signals sent out or received from various connectors on the rear panel. Learn more about External and AUX Triggering.

Manual Trigger! - Manually sends one trigger signal to the VNA. Available ONLY when Manual trigger is selected.

 

Trigger Scope

These settings determine what is triggered.

Global - Triggers  sent to all triggerable channels. One trigger will sweep all channels that are triggerable. [Default setting]

Channel - A trigger is sent to the current channel, but the channel is incremented to the next triggerable channel after the current channel is complete.

Active Channel - Trigger are sent only to the active channel. The active channel does not change.

 

Channel Trigger State

These settings determine how many trigger signals the channel will accept.

Continuous - The channel accepts an infinite number of trigger signals.

Groups - The channel accepts only the number of trigger signals that is specified in the Number of Groups text box, then goes into Hold. Before selecting groups you must first increment the Number of Groups text box to greater than one.

Number of Groups - Specify the number of triggers the channel accepts before going into Hold. If in Point Sweep, an entire sweep is considered one group.

First increment to desired number, then select 'Groups'.

Single - The channel accepts ONE trigger signal, then goes into Hold.

Another way to trigger a single measurement is to set Trigger Source to Manual, then send a Manual trigger. However, ALL channels are single triggered.

Hold - The channel accepts NO trigger signals.

 

Trigger Mode

These settings determine what EACH signal will trigger.

Sweep and Point modes are available ONLY when both Trigger Source = MANUAL or EXTERNAL AND Trigger Scope = CHANNEL.

  • Channel - Each trigger signal causes ALL traces in that channel to be swept in the order specified below.

  • Point - Each Manual or External trigger signal causes one data point to be measured. Subsequent triggers go to the same trace until it is complete, then other traces in the same channel are swept in the order specified below. When in Groups or Single trigger, the count is decremented by one after ALL data points on ALL traces in the channel are measured.  See Also, the (point) Sweep Indicator and SCPI Triggering example for use with External.

  • Trace - Available ONLY when Point Sweep is selected. Each trigger signal causes two identical measurements to be triggered separately - one trigger signal is required for each measurement. Other trigger mode settings cause two identical parameters to be measured simultaneously.  Trace triggering is NOT permitted when a channel is using a 2 port (or more) S-Parameter calibration.

  • Sweep - Each Manual or External trigger signal causes ALL traces that share a source port to be swept in the order specified below. When in Groups or Single trigger, the count is decremented by one after ALL traces in ALL directions are swept.

When multiport correction is ON, which requires sweeps in more than one direction, traces on the screen will not update until all of the relevant directions have been swept. For example, with all four 2-port S-Parameters displayed:

    • When Full 2-port correction is ON, trigger 1 causes NO traces to update; trigger 2 causes ALL S-Parameters to update. Learn more about sweeps with correction ON.

    • When correction is OFF, trigger 1 causes S11 and S21 to update; trigger 2 causes S22 and S12 to update.

Trace Sweep Order

For ALL Trigger Modes, trigger signals continue in the same channel until all traces in that channel are complete. Triggering then continues to the next channel that is not in HOLD.

Traces within each channel are always swept in the following order:

  • Traces are swept sequentially in source-port order. For example, in a channel with all four 2-port S-parameters, first the source port 1 traces (S11 and S21) are swept simultaneously. Then the source port 2 traces (S22 and S12) are swept simultaneously.

Restart - (Available only from the Trigger menu) Channels in Hold are set to single trigger (the channel accepts a single trigger signal). All other settings are unaffected, including decrementing trigger Groups.

See Also

Last modified:

18-May-2016

First Release