Fourier Transform
From Python Wiki
Introduction
The Fourier transform is a method for representing a time domain signal in the frequency domain. This transform is discussed in the tutorial: Shock_and_Vibration_Signal_Analysis.pdf
Utility
The scripts on this page require the utility module tompy.py
Fourier Transform
An example of a Fourier transform script is fourier.py
The corresponding inverse Fourier transform script is invfourier.py
Fast Fourier Transform (FFT)
The processing time for taking the transform of a long time history can be dramatically decreased by using an FFT.
An FFT can be performed if the time history has 2n coordinate points, where n is an integer. A time history can be truncated or zero-padded if necessary so that it meets this requirement.
Scipy has an FFT in its numerical library.
from scipy.fftpack import fft
An example of a script using this function is: fft.py
The corresponding inverse FFT script is: invfft.py
Waterfall FFT
The Waterfall script generates a 3D plot using:
from mpl_toolkits.mplot3d.art3d import Poly3DCollection
The script: waterfall_FFT.py
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