About Triggering (Input)

Triggering allows you to capture a block of time data around a particular event. This event can be in the time domain or the frequency domain. Once the time data has been captured by the measurement hardware and transferred to the 89600 VSA software, the VSA begins processing the data.

See Trigger Tab for parameter descriptions.

Trigger Styles

The first parameter to select when setting up your trigger is the trigger Style. This determines the source of your trigger event (e.g. external trigger, periodic trigger, magnitude before or after IF conversion, frequency-domain, etc.).

Available trigger styles vary depending on the connected measurement hardware and options. For hardware specific trigger information, see the Available Measurement Hardware topic and follow the link to your specific measurement hardware.

Setting up a Trigger Condition

Trigger setup parameters are located in the Trigger Tab. The Trigger dialog includes parameters that apply to both the time-domain trigger styles and the Frequency Mask trigger style.

Those parameters not available for the particular trigger style chosen or for the hardware configuration being used will be grayed out on the Trigger tab.

When Data Acquisition Begins

The measurement hardware starts capturing data when a valid trigger is detected. A valid trigger occurs when the trigger condition (combination of relevant trigger parameters) is satisfied.

Trigger delay adjusts when the hardware captures data. If the delay is zero, the hardware takes data immediately after the trigger event. Trigger Delay may be positive (post-trigger delay) or negative (pre-trigger delay).

For post-trigger delay, the hardware starts capturing data once the Trigger Delay time has elapsed after the trigger event. In other words, the first point in the Main Time trace will have a time value equal to the delay (t=Trigger Delay).

For pre-trigger delay, the time record from the hardware will start at a time equal to the Trigger Delay before the trigger event occurs. The hardware uses its capture buffer to accomplish this. In this case, the first point in the Main Time trace will have a time value that is negative and equal to the Trigger Delay.

Delay can be entered in seconds, milliseconds, or microseconds. For pre-trigger delay, enter a negative value (as in -10 ms). For post-trigger delay, enter a positive value (as in 10 ms).

If triggering is not behaving as expected, see Trigger Level and Delay Issues.

Using Trigger Hold-off

Trigger hold-off is defined differently for the three hold-off styles. See Hold-off style and Hold-off for more details.

Trigger Out

Trigger Out selects the desired trigger output connector to use on the currently connected instrument. See Trigger Out for a detailed description.