188
Keysight InfiniiVision 3000 X-Series Oscilloscopes User's Guide
12
Acquisition Control
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.
Oscilloscope Bandwidth Required
The oscilloscope bandwidth required to accurately measure a signal is primarily
determined by the signal's rise time, not the signal's frequency. You can use these
steps to calculate the oscilloscope bandwidth required:
1
Determine the fastest edge speeds.
You can usually obtain rise time information from published specifications for
devices used in your designs.
2
Compute the maximum "practical" frequency component.
From Dr. Howard W. Johnson's book,
High-Speed Digital Design – A
Handbook of Black Magic
, all fast edges have an infinite spectrum of frequency
components. However, there is an inflection (or "knee") in the frequency
spectrum of fast edges where frequency components higher than f
knee
are
insignificant in determining the shape of the signal.
f
knee
= 0.5 / signal rise time (based on 10% - 90% thresholds)
f
knee
= 0.4 / signal rise time (based on 20% - 80% thresholds)
3
Use a multiplication factor for the required accuracy to determine the
oscilloscope bandwidth required.
See Also
Choosing an Oscilloscope with the Right Bandwidth for your Application
, Keysight
Application Note 1588
(
http://literature.cdn.keysight.com/litweb/pdf/5989-5733EN.pdf
)
Required accuracy
Oscilloscope bandwidth required
20%
f
BW
= 1.0 x f
knee
10%
f
BW
= 1.3 x f
knee
3%
f
BW
= 1.9 x f
knee
Содержание InfiniiVision 3000 X Series
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Страница 48: ...48 Keysight InfiniiVision 3000 X Series Oscilloscopes User s Guide 1 Getting Started...
Страница 62: ...62 Keysight InfiniiVision 3000 X Series Oscilloscopes User s Guide 2 Horizontal Controls...
Страница 72: ...72 Keysight InfiniiVision 3000 X Series Oscilloscopes User s Guide 3 Vertical Controls...
Страница 122: ...122 Keysight InfiniiVision 3000 X Series Oscilloscopes User s Guide 6 Digital Channels...
Страница 128: ...128 Keysight InfiniiVision 3000 X Series Oscilloscopes User s Guide 7 Serial Decode...
Страница 134: ...134 Keysight InfiniiVision 3000 X Series Oscilloscopes User s Guide 8 Display Settings...
Страница 182: ...182 Keysight InfiniiVision 3000 X Series Oscilloscopes User s Guide 11 Trigger Mode Coupling...
Страница 200: ...200 Keysight InfiniiVision 3000 X Series Oscilloscopes User s Guide 12 Acquisition Control...
Страница 210: ...210 Keysight InfiniiVision 3000 X Series Oscilloscopes User s Guide 13 Cursors...
Страница 252: ...252 Keysight InfiniiVision 3000 X Series Oscilloscopes User s Guide 15 Mask Testing...
Страница 256: ...256 Keysight InfiniiVision 3000 X Series Oscilloscopes User s Guide 16 Digital Voltmeter...
Страница 290: ...290 Keysight InfiniiVision 3000 X Series Oscilloscopes User s Guide 19 Print Screens...
Страница 324: ...324 Keysight InfiniiVision 3000 X Series Oscilloscopes User s Guide 21 Web Interface...
Страница 344: ...344 Keysight InfiniiVision 3000 X Series Oscilloscopes User s Guide 22 Reference...
Страница 370: ...370 Keysight InfiniiVision 3000 X Series Oscilloscopes User s Guide 24 FlexRay Triggering and Serial Decode...
Страница 424: ...424 Keysight InfiniiVision 3000 X Series Oscilloscopes User s Guide 28 UART RS232 Triggering and Serial Decode...