Triggering on entering or leaving a defined window

 
The analogue trigger input is continuously sampled at the selected sample rate. If its signal leaves a user programmed window, defined by a higher and lower threshold level, then a valid trigger is seen and acted upon so that signal replay (waveform generation) starts. The green trace shows when the condition has been met for a valid trigger. During replay further trigger events are ignored until the replay period has completed. Programmed window levels are simply made in the appropriate code register of the driver software. The level is defined in millivolts allowing for fine adjustment. Window trigger. Diagram an trigger input signal leaving an amplitude window to be recognised as a trigger event.
 
Alternatively the window trigger also works for situations where the incoming trigger signal enters the defined window, this choice is also made by the programmer in the appropriate register. Window trigger. Diagram an trigger input signal entering an amplitude window to be recognised as a trigger event.
 
Note that in both diagrams above the "Start" indicates the point at which the card was armed ready to receive triggers, here the start occurred when the trigger condition was already fulfilled, so instantly the card starts to replay. The start could be at any point in time as determined by the user and his application.

Window trigger mode can be combined in a AND / OR logic arrangement with other sources, e.g. a software trigger (such as key press), or the card's LVTTL trigger input. The above is just a summary of the pulsewidth features. Full details of the window triggering operation can be found in the user manual.

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