ADLINK PXI-2208 - Manual (Page 86)

74 Operation Theory
Inside-Region Analog Trigger Condition
Figure 4-34 shows the inside-region analog trigger condition,
the trigger signal is generated when the input analog signal
level falls in the range between the High_Threshold and the
Low_Threshold voltages.
NOTE The High_Threshold setting should be always higher
than the Low_Threshold voltage setting.
Figure 4-34: Inside-Region Analog Trigger Condition
High-Hysteresis Analog Trigger Condition
Figure 4-35 shows the high-hysteresis analog trigger condition,
the trigger signal is generated when the input analog signal
level is greater than the High_Threshold voltage, and the
Low_Threshold voltage determines the hysteresis duration.
Note the High_Threshold setting should be always higher then
the Low_Threshold voltage setting.