13.1 Overview and Features
207
13
Chap
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13 FFT
Fun
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FFT analysis can only be used with the FFT function.
The FFT (Fast-Fourier Transform) functions provide frequency analysis of input signal data.
Use these functions for frequency analysis of rotating objects, vibrations, sounds and etc.
For details, refer to "Appendix 5 FFT Definitions"(
Analysis can be performed on data as it is being measured, on pre-existing analog waveform data previ-
ously acquired with the Memory function, and on data output from waveform calculations.
When using Model 8968 High Resolution Unit equipped with an anti-aliasing filter, the cut-off frequency
can be automatically set by linking with the frequency range setting.
Major Features
•FFT analysis frequency range: 133 mHz to 8 MHz
•FFT Analysis Modes (16 types)
* Not available when using external sampling.
For phase spectra, only the required phase information is highlighted and displayed.
See:
"13.3.8 Emphasizing Analysis Results (phase spectra only)" (
so, when performing FFT analysis with the instrument connected to a sound level or vibration meter, scal-
ing by dB can be set from the Channel Settings screen if you want to read values directly in calibrated
units of measurement.
See:
Refer to the "17.2.4 FFT Function" (
p.299) for FFT function specifications.
FFT Function
Chapter 13
13.1 Overview and Features
• Storage Waveform
• Cross-power Spectrum
• Histogram
• Impulse Response
• Linear Spectrum
• Coherence Function
• RMS Spectrum
• Phase Spectrum
• Power Spectrum
• Auto-correlation Function
• Power Spectrum Density*
• Cross-correlation Function
• LPC analysis (Power Spectrum
Density)
*
• 1/1 Octave Analysis*
• Transfer Function
• 1/3 Octave Analysis*
To suppress the effects of aliasing distortion
We recommend using Model 8968 High Resolution Unit that are equipped with anti-aliasing filtering
to suppress the effects of aliasing distortion when sampling.
See:
Aliasing Distortion and Anti-Aliasing Filters
Summary of Contents for 8847
Page 1: ...MEMORY HiCORDER Instruction Manual 8847 December 2010 Revised edition 4 8847A981 04 10 12H ...
Page 2: ......
Page 18: ...Operating Precautions 8 ...
Page 26: ...1 4 Basic Key Operations 16 ...
Page 74: ...4 4 Waveform Observation 64 ...
Page 98: ...5 5 Managing Files 88 ...
Page 110: ...6 6 Miscellaneous Printing Functions 100 ...
Page 126: ...7 8 Seeing Block Waveforms 116 ...
Page 160: ...8 10 Making Detailed Settings for Input Modules 150 ...
Page 198: ...10 6 Numerical Calculation Type and Description 188 ...
Page 296: ...15 7 Controlling the Instrument with Command Communications LAN USB 286 ...
Page 304: ...16 2 External I O 294 ...
Page 362: ...Appendix 5 FFT Definitions A28 ...
Page 368: ...Index Index 6 ...
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