FFT Spectral Analysis
4
Keysight InfiniiVision 3000T X-Series Oscilloscopes User's Guide
95
For more information on the use of FFTs please refer to Keysight Application Note
243,
The Fundamentals of Signal Analysis
at
http://literature.cdn.keysight.com/litweb/pdf/5952-8898E.pdf
. Additional
information can be obtained from Chapter 4 of the book
Spectrum and Network
Measurements
by Robert A. Witte.
FFT Units
FFT (Magnitude)
Units
FFT units are displayed as dB.
FFT (Phase) Units
In this case, the vertical units are degrees or radians.
FFT DC Value
The FFT computation produces a DC value that is incorrect. It does not take the
offset at center screen into account. The DC value is not corrected in order to
accurately represent frequency components near DC.
FFT Aliasing
When using FFTs, it is important to be aware of frequency aliasing. This requires
that the operator have some knowledge as to what the frequency domain should
contain, and also consider the sampling rate, frequency span, and oscilloscope
vertical bandwidth when making FFT measurements. The FFT resolution (the
quotient of the sampling rate and the number of FFT points) is displayed directly
above the softkeys when the FFT Menu is displayed.
NOTE
Nyquist Frequency and Aliasing in the Frequency Domain
The Nyquist frequency is the highest frequency that any real-time digitizing oscilloscope can
acquire without aliasing. This frequency is half of the sample rate. Frequencies above the
Nyquist frequency will be under sampled, which causes aliasing. The Nyquist frequency is also
called the folding frequency because aliased frequency components fold back from that
frequency when viewing the frequency domain.
Содержание DSOX3012T
Страница 78: ...78 Keysight InfiniiVision 3000T X Series Oscilloscopes User s Guide 2 Horizontal Controls...
Страница 88: ...88 Keysight InfiniiVision 3000T X Series Oscilloscopes User s Guide 3 Vertical Controls...
Страница 98: ...98 Keysight InfiniiVision 3000T X Series Oscilloscopes User s Guide 4 FFT Spectral Analysis...
Страница 148: ...148 Keysight InfiniiVision 3000T X Series Oscilloscopes User s Guide 7 Digital Channels...
Страница 154: ...154 Keysight InfiniiVision 3000T X Series Oscilloscopes User s Guide 8 Serial Decode...
Страница 160: ...160 Keysight InfiniiVision 3000T X Series Oscilloscopes User s Guide 9 Display Settings...
Страница 232: ...232 Keysight InfiniiVision 3000T X Series Oscilloscopes User s Guide 13 Acquisition Control...
Страница 242: ...242 Keysight InfiniiVision 3000T X Series Oscilloscopes User s Guide 14 Cursors...
Страница 288: ...288 Keysight InfiniiVision 3000T X Series Oscilloscopes User s Guide 16 Mask Testing...
Страница 294: ...294 Keysight InfiniiVision 3000T X Series Oscilloscopes User s Guide 17 Digital Voltmeter and Counter...
Страница 300: ...300 Keysight InfiniiVision 3000T X Series Oscilloscopes User s Guide 18 Frequency Response Analysis...
Страница 320: ...320 Keysight InfiniiVision 3000T X Series Oscilloscopes User s Guide 19 Waveform Generator...
Страница 340: ...340 Keysight InfiniiVision 3000T X Series Oscilloscopes User s Guide 21 Print Screens...
Страница 374: ...374 Keysight InfiniiVision 3000T X Series Oscilloscopes User s Guide 23 Web Interface...
Страница 394: ...394 Keysight InfiniiVision 3000T X Series Oscilloscopes User s Guide 24 Reference...
Страница 416: ...416 Keysight InfiniiVision 3000T X Series Oscilloscopes User s Guide 25 CAN LIN Triggering and Serial Decode...
Страница 426: ...426 Keysight InfiniiVision 3000T X Series Oscilloscopes User s Guide 26 CXPI Triggering and Serial Decode...
Страница 436: ...436 Keysight InfiniiVision 3000T X Series Oscilloscopes User s Guide 27 FlexRay Triggering and Serial Decode...
Страница 480: ...480 Keysight InfiniiVision 3000T X Series Oscilloscopes User s Guide 30 Manchester NRZ Triggering and Serial Decode...
Страница 510: ...510 Keysight InfiniiVision 3000T X Series Oscilloscopes User s Guide 32 SENT Triggering and Serial Decode...
Страница 520: ...520 Keysight InfiniiVision 3000T X Series Oscilloscopes User s Guide 33 UART RS232 Triggering and Serial Decode...