Technical data

22 4000 X-Series Oscilloscopes Advanced Training Guide
2 Oscilloscope Familiarization Labs
You should now see on your scope’s display an expansion of just the 3rd
pulse in this burst in the lower portion of the display as should in
Figure 10. And the + Width measurement should be measuring the positive
pulse width of just the 3rd pulse.
Figure 10 Using the scope’s Zoom timebase mode to perform “gated” measurements.