HP 54616B User And Service Manual page 35

Figure 2-2 shows the time reference set to center. Notice that the markers
expand around the area of interest. You can place the markers over the area
of interest with the delay knob, then expand the delayed sweep with the time
base knob to increase the resolution.
Figure 2-2
Delayed sweep
markers
Time reference set to center
Operating Your Oscilloscope
To use delayed sweep
2–5