Front-Panel Overview Important Oscilloscope Considerations - HP 54645A User's And Service Manual

Front-Panel Overview
Important Oscilloscope Considerations
The simplest averaging is "smoothing." For example, the sample rate at a
Time/Div setting of 2 s/div allows the extra 5-ns samples to be smoothed
together, smoothing the data into one sample, which is then displayed. As
with Peak Detect, smoothing has no effect at less than 2 s/div. Smoothing
works on a single acquisition (even untriggered and single-shot). Averaging
(4, 8, 16, 32, 64, 128, and 256) needs a stable trigger, because in this mode
multiple acquisitions are averaged together. See the chapter "MegaZoom
Concepts and Oscilloscope Operation" for more information about smoothing.
Auto Single
As in Normal run mode, auto-trigger will generate a trigger for you if one is
not found in the predetermined time from when the trigger system is armed.
To take a single-shot acquisition, if you are not particularly interested in
triggering the acquisition (for example, if you are probing a known signal),
use Auto Single mode. If a trigger exists, it will be used; if a trigger does not
exist, an untriggered or auto-triggered acquisition will be taken for later
analysis.
Using Vectors
One of the most fundamental choices you must make about your display is
whether to draw vectors (connect the dots) between the samples, or simply
let the samples fill in the waveform. To some degree, this is a matter of
personal preference, but it also depends on the waveform.
You will probably operate the oscilloscope most often with vectors on.
Having vectors on slows the display of the oscilloscope, thus works better
for slower sweep speeds, peak detect, or average displays, and signals with
stable triggers.
Having vectors off works better for fast sweep speeds, normal displays, or
unstable triggers. Complex analog signals like video and eye diagrams
show more intensity information with vectors off. Turn vectors off when
the maximum display rate is required, or when highly complex or
multi-valued waveforms are displayed.
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