Trigger auto re-arm on positive or negative edges

 
The analogue trigger input is continuously sampled at the selected sample rate. If the user programmed re-arm level is crossed by the trigger signal from lower to higher values (rising edge) then the trigger engine is armed. When the separately set trigger level is now crossed the card will start recording or replaying data depending on functionality, (A/D digitiser or D/A waveform generator). Further triggers are ignored until the record / replay period has completed, then the trigger engine will accept a new re-arm ready for the next trigger. This trigger mode can be combined with AND or OR logic from other sources, e.g. a software trigger (such as key press), from the LVTTL trigger input connector, or any analogue signal input channel (A/D digitiser cards only). Edge trigger. Diagram showing positive edge re-arm point in relation to the varying analogue trigger signal.
 
Auto re-arm also works for higher to lower value (falling edge) situations, where required. Choice of slope is simply made by the programmer in the appropriate register. Diagram showing negative edge re-arm point in relation to the varying analogue trigger signal
 
Hint: The re-arm option is very useful in situations where noisy signal could result in false triggers, i.e when the trigger recording / replay is desired only after a major amplitude in a certain direction.

DataQuest Solutions Ltd. | Phone: 01526 557171 | Email: info@dqsolutions.co.uk