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Chapter 3
Acquiring Analog Input
When using hysteresis with a falling slope, the trigger is armed when the signal starts above
Level, plus the hysteresis value, and asserts when the signal crosses below Level. For example,
if you add a hysteresis of 1 V to a level of 3.2 V, the signal must start at or rise above 4.2 V to
arm the trigger. The trigger asserts as the signal falls below 3.2 V and deasserts when it rises
above 4.2 V, as shown in Figure 3-12.
Figure 3-12.
Analog Edge Triggering with Hysteresis on Falling Slope
Window Triggering
A window trigger occurs when an analog signal either passes into (enters) or passes out of
(leaves) a window defined by two levels. Specify the levels by setting a value for the top and
bottom window boundaries. Figure 3-13 demonstrates a trigger that acquires data when the
signal enters the window. You can also program the trigger circuit to acquire data when the
signal leaves the window.
Figure 3-13.
Window Triggering
Level
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Hy
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4.2 V
3
.2 V
Reference Trigger
Window Top
Window Bottom
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Reference Trigger
