Figure 2-23. Analog Level Trigger On Rising Slope; Figure 2-24. Analog Edge Triggering With Hysteresis On Rising Slope - National Instruments SC Express NI PXIe-4339 User Manual

Chapter 2 Using the Module
Analog Edge Triggering
For analog edge triggering, configure the module to detect a certain signal level and slope, either
rising or falling. Figure 2-23 shows an example of rising edge analog triggering. The analog
comparison becomes true when the signal starts below Level and then crosses above Level.
3.2 mV/V
Analog Comparison
Reference Trigger
Analog Edge Triggering With Hysteresis
When you add hysteresis to analog edge triggering, you add a window above or below the trigger
level. This triggering mode often is used to reduce false triggering due to noise or jitter in the
signal. For example, if you add a hysteresis of 1 mV/V to the example in Figure 2-23, which
uses a level of 3.2 mV/V, the signal must start at or drop below 2.2 mV/V to arm the trigger.
The analog comparison becomes true when the signal rises above 3.2 mV/V and becomes false
when it falls below 2.2 mV/V, as shown in Figure 2-24.

Figure 2-24. Analog Edge Triggering with Hysteresis on Rising Slope

3.2 mV/V
2.2 mV/V
Analog Comparison
Reference Trigger
2-32 | ni.com

Figure 2-23. Analog Level Trigger on Rising Slope

0
Level
Hysteresis
Level and Slope of
Signal Initiates Data Capture
Level