LeCroy DDA 7 Zi series, Operator'S Manual

Page: 262 / 544

WavePro 7Zi
261
WP700Zi-OM-E-RevA
Hold Off by Time
Sometimes you can achieve a stable display of complex, repetitive waveforms by placing a condition on the time
between each successive trigger event. This time would otherwise be limited only by the input signal, the
coupling, and the instrument's bandwidth. Select a positive or negative slope, and a minimum time between
triggers. The trigger is generated when the condition is met after the selected holdoff time, counted from the last
trigger. The delay is initialized and started on each trigger.
Figure 4-25. Edge Trigger with Holdoff by Time. The bold edges on the trigger source indicate that a
positive slope has been selected. The broken upward-pointing arrows indicate potential triggers, which
would occur if other conditions are met. The bold arrows indicate where the triggers actually occur when
the holdoff time has been exceeded.
Hold Off by Events
Select a positive or negative slope and a number of events. An event is the number of times the trigger condition
is met after the last trigger. A trigger is generated when the condition is met after this number, counted from the
last trigger. The count is restarted on each trigger. For example, if the event number is two, the trigger will occur
on the third event.
Figure 4-26. Edge Trigger with Holdoff by Events (in this example, two events). The bold edges on the
trigger source indicate that a positive slope has been selected. The broken, upward-pointing arrows
indicate potential triggers, while the bold ones show where triggers actually occur after the holdoff
expires.
Optimizing for High Frequency
Some X-Stream instruments give you an option to reject high or low frequencies by means of a checkbox
. By default, the checkbox is selected, meaning, the instrument is optimized for high
frequency waveforms. However, if you are measuring a waveform that is 10 MHz or slower, the checkbox should
be unchecked to avoid triggering on an incorrect slope.