Keysight DSOX1202A - Oscilloscope Rise Time

Acquisition Control 13
Keysight InfiniiVision 1200 X-Series and EDUX1052A/G Oscilloscopes User's Guide 133
So, in practice, an oscilloscope's sample rate should be four or more times its
bandwidth: f
S
=4f
BW
. This way, there is less aliasing, and aliased frequency
components have a greater amount of attenuation.
See Also Evaluating Oscilloscope Sample Rates vs. Sampling Fidelity: How to Make the
Most Accurate Digital Measurements, Keysight Application Note 1587
(http://literature.cdn.keysight.com/litweb/pdf/5989-5732EN.pdf)
Oscilloscope Rise Time
Closely related to an oscilloscope's bandwidth specification is its rise time
specification. Oscilloscopes with a Gaussian-type frequency response have an
approximate rise time of 0.35/f
BW
based on a 10% to 90% criterion.
An oscilloscope's rise time is not the fastest edge speed that the oscilloscope can
accurately measure. It is the fastest edge speed the oscilloscope can possibly
produce.
Figure 23 Sample Rate and Oscilloscope Bandwidth
Limiting oscilloscope bandwidth (f
BW
) to 1/4 the sample rate (f
S
/4)
reduces frequency components above the Nyquist frequency (f
N).
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