2-19
Front-Panel Overview
To operate the time base controls
To operate the time base controls
The following exercise guides you through the time base keys, knobs, and status
line.

• Turn the Horizontal sweep speed (time/division) knob and notice the

change it makes to the status line.

The sweep speed knob changes the sweep speed from 5ns/div to 50s/div for
the 54620-series and 1 ns/div to 50 s/div for the 54640-series in a 1-2-5 step
sequence, and the value of the sweep speed is displayed in the status line at the
top of the display.
•Press the Main/Delayed, then press the Vernier softkey.
The Vernier softkey allows you to change the sweep speed in smaller increments
with the time/div knob. These smaller increments are calibrated, which results
in accurate measurements, even with the vernier turned on.

• Turn the delay time knob ( ) and notice that its value is displayed in

the status line.

The delay knob moves the main sweep horizontally, and it pauses at 0.00 s,
mimicking a mechanical detent. At the top of the graticule is a solid triangle
(▼) sy m b o l a n d a n o p e n tr i a n gl e ( ∇) s ym b o l . T h e ▼ symbol indicates the trigger
point and it moves with the Delay time knob. The ∇ symbol indicates the time
reference point and is also where the zoom-in/zoom-out is referenced. If the
Time Re f sof tkey i s set t o Left, the ∇ is located one graticule in from the left side
of the display. If the Time Ref softkey is set to Center, the ∇ is located at the
center of the display. If the Time Ref softkey is set to Right, the ∇ is located on e
graticule in from the right side of the display. The delay number tells you how
far the time reference point ∇ is located from the trigg er point ▼.
All events displayed left of the trigger point ▼ happened before the trigger
occurred, and these events are called pre-trigger information. You will find this
fea tu re ve ry u se fu l b ec au s e y ou ca n n ow s ee th e e ve nt s th at le d u p t o th e t ri gg er
point. Everything to the right of the trigger point ▼ is called post-trigger
information. The amount of delay range (pre-trigger and post-trigger
information) available depends on the sw eep speed selected.