HP 1652B Getting Started Manual page 398

Channel Menu
2346
Normally 500 points of the 2k waveform record is displayed on screen.
Change the sweep speed to 500 us/div. Now all 2k of the waveform
record is compressed and displayed on screen. See figure 23-16.
-.
(Scope]- Llavef arms
fau to-Measure
[ Off
] Display 1 Fcormal 1 Connect dots[]
Sample perioa - 1.000 us
prEq
Delay
I
Grid pF--
1
1
Figure 2346. Compressed Waveform
Now change the sweep speed to 2 us/Div. At 200 us/Div, 500 points
were displayed; at 2 us/Div, only 20 points are displayed. When the
waveform is expanded, the oscilloscope uses a reconstruction filter to
fill in the waveform points to provide a more useable display. When
used in conjunction with scrolling (see "Delay Field" paragraph),
zooming is very useful in displaying single-shot waveforms.
HP 1652B/16538
Front-Panel Reference