146 Agilent InfiniiVision 3000 X-Series Oscilloscopes User's Guide
10 Triggers
 
Edge then Edge Trigger
The Edge then Edge trigger mode triggers when the Nth edge occurs after 
an arming edge and a delay period.
The arm and trigger edges can be specified as   (Rising) or   (Falling) 
edges on analog or digital channels.
1 Press the [Trigger] key.
2 In the Trigger Menu, press the Trigger softkey; then, turn the Entry knob 
to select Edge then Edge.
3 Press the Sources softkey.
4 In the Edge then edge Sources Menu: