A digital edge trigger acts on the rising or falling edge of a digital signal.

A digital signal has two discrete levels: a high level and a low level. When the signal transitions from high to low or from low to high, a digital edge is created.

There are two types of edges:
  • Rising—Occurs when the signal transitions from low level to high level.
  • Falling—Occurs when the signal transitions from high level to low level.

    • Triggers configured to act on a rising or a falling edge of a digital signal are called edge triggers. Digital triggering is possible on the RTSI lines, PFI lines, and the PXI Star Trigger line.

    As the following figure shows, an edge trigger could be configured to occur either at the Falling Edge of Signal or Rising Edge of Signal.

    Figure 7. Configuring the Edge Trigger