Agilent Technologies DSO-X 4022A, Руководство пользователя

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66 Agilent InfiniiVision 4000 X-Series Oscilloscopes User's Guide
2
Horizontal Controls
Figure 2 shows the trigger point with the delay time set to 200 µs. The
delay time number tells you how far the time reference point is located
from the trigger point. When delay time is set to zero, the delay time
indicator overlays the time reference indicator.
All events displayed left of the trigger point happened before the trigger
occurred. These events are called pre- trigger information, and they show
events that led up to the trigger 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 time/div selected and memory
depth.
The horizontal position knob works (in the Normal time mode) while
acquisitions are running or when they are stopped. When running,
adjusting the horizontal scale knob changes the sample rate. When
stopped, adjusting the horizontal scale knob lets you zoom into acquired
data. See
"Panning and Zooming Single or Stopped Acquisitions" on
page 66.
Note that the horizontal position knob has a different purpose in the
Zoom display. See
"To display the zoomed time base" on page 71.
Panning and Zooming Single or Stopped Acquisitions
When the oscilloscope is stopped, use the horizontal scale and position
knobs to pan and zoom your waveform. The stopped display may contain
several acquisitions worth of information, but only the last acquisition is
available for pan and zoom.
The ability to pan (move horizontally) and scale (expand or compress
horizontally) an acquired waveform is important because of the additional
insight it can reveal about the captured waveform. This additional insight
is often gained from seeing the waveform at different levels of abstraction.
You may want to view both the big picture and the specific little picture
details.
The ability to examine waveform detail after the waveform has been
acquired is a benefit generally associated with digital oscilloscopes. Often
this is simply the ability to freeze the display for the purpose of
measuring with cursors or printing the screen. Some digital oscilloscopes