Triggering within or outside a defined window

The analogue trigger input is continuously sampled at the selected sample rate. If the user programmed window, defined by a higher and lower threshold level is exceeded by the incoming signal, then a valid trigger is seen and acted upon so that recording starts. During recording further trigger events are ignored until the recording period has completed. Note that this trigger mode can be combined with AND or OR logic from other sources, e.g. a software trigger (such as key press), the connector dedicated to a TTL trigger input, or analogue signal channel (not to be confused with the analogue trigger input this "analogue signal channel" is where the signal for recording enters). The green trace shows when this high level trigger will be valid for the logic combination. A programmed levels are simply made by the programmer in the appropriate register of the driver software.
Alternatively the window trigger also works for situations where the incoming trigger signal goes outside the window, this choice is also made by the programmer in the appropriate register.
Note that in both diagrams above the "START" indicates the point at which the card was started ready to receive triggers, here the start occurred when the trigger condition was already fulfilled, so instantly the card starts to record. The "start" could be at any point in time as determined by the user and his application.