Acquiring and Displaying Waveforms
3–42 TDS 684A, TDS 744A, & TDS 784A User Manual
zoom factor halves the time enclosed by either box and, therefore, halves the
minimum offset time.
The oscilloscope retains any value input that is less than the minimum time
available as a “request” if you enter that value using the keypad. Increasing the
zoom factor or decreasing the horizontal scale to a setting that allows the
requested value sets offset time to that value. You cannot set offset to less than
the minimum offset time available when using the general purpose knob.
Selected Graticule
Zoomed Waveform Edges
Zoom Boxes
Unzoomed Waveform
Figure 3–25: Dual Zoom — Shown Dual Window (Preview) Mode
NOTE. To make setting up Dual Zoom easier, turn on Preview in the side menu.
In this dual-window mode, the zoomed display appears in the top graticule,
while the lower graticule shows the two zoomed portions enclosed in two boxes
on the unzoomed waveform. Adjusting offset moves the right box relative to the
left box, which remains stationary. The associated zoomed waveform in the
upper graticule moves to track the offset changes. You can also adjust the
waveform relative to the zoom boxes by selecting the lower graticule and
adjusting the vertical and horizontal control knobs. See Using Dual Window
Mode on page 3–40.