Trigger hysteresis

All oscilloscope channel trigger types use one or two trigger hystereses. The hysteresis defines the distance between the firing level and the arming level and determines the sensitivity of the trigger system. A small hysteresis means that the arming and firing level are close to each other and a small signal change will be enough to cause a trigger. A large hysteresis means that the signal change must be large before a trigger is generated. This makes the trigger system less sensitive to noise.

Trigger hysteresis can be set for each channel individually. Changing the trigger hysteresis of a channel in the Multi Channel oscilloscope software can be done in various different ways:

  • Dragging/moving an edge of the trigger symbol (Rising edge symbol, Falling edge symbol, etc.) on an axis of an oscilloscope channel that is used as trigger source.
  • Opening the trigger properties dialog and adjusting the required trigger hysteresis.
  • Right-clicking the trigger symbol on an axis or the associated channel in the Object Tree and selecting Trigger hysteresis or Trigger hysteresis 2 in the popup menu. The hysteresis can then be set as a percentage of the full scale input range of the channel by selecting one of the pre defined percentage values. The corresponding voltage is also displayed. A User defined... setting is available that also allows to set the trigger hysteresis as a voltage.
  • Using hotkeys [ and ] in combination with the appropriate channel selection hotkey(s) (only trigger hysteresis 1).
  • Clicking the increase/decrease trigger hysteresis buttons Increase trigger hysteresis and Decrease trigger hysteresis on the channel toolbar (only trigger hysteresis 1).