|5991-0662EN Bandwidth and Rise Time Requirements for Making Accurate Oscilloscope Measurements c2014||Keysight Technologies
Bandwidth and Rise Time Requirements for
Making Accurate Oscilloscope Measurements
How much oscilloscope bandwidth do you need and how fast does the rise time need to be to
measure your signals accurately? Oscilloscope users ask this question regularly, but getting a good
answer is typically dificult. The answer depends on the frequency response roll-off characteristics
of the signal under test (SUT); it must be down about 15 db or more at the scope bandwidth. Most
users don't know the roll-off characteristics of their signals, so this answer isn't likely to be useful.
The roll-off characteristics will largely determine the amount of overshoot present in the step
response of the SUT, so it may be more useful to have some "rules of thumb" for the bandwidth and
rise time margin you need, based on the amount of overshoot.
To that end, we ran simulations in A|