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Discrete Fourier Transform (DFT)

Snippet from Wikipedia: Discrete Fourier transform

In mathematics, the discrete Fourier transform (DFT) converts a finite list of equally spaced samples of a function into the list of coefficients of a finite combination of complex sinusoids, ordered by their frequencies, that has those same sample values.

A discrete fourier transform (DFT) algorithm is based on the jWave package. This is a simple example of transformation of 1D array:

dft.py
from math.jwave import Transform
from math.jwave.transforms import *
t=Transform( DiscreteFourierTransform( ) )
arrTime = [1., 10., 12., 8., 1., 1., 1., 1. ]
arrFreq = t.forward( arrTime ) # 1-D DFT forward
print arrFreq.tolist()
arrReco = t.reverse( arrFreq ) # 1-D DFT reverse
print arrReco.tolist()

The output of this script is:

[3.75, 5.0, 1.75, -0.5, -2.7499, 0.4999, -1.750, 5.0]
[1.0, 10.0, 12.0, 8.0, 1.0, 1.0, 1.0, 1.0]
man/dsignal/dft.txt · Last modified: 2014/01/07 16:47 (external edit)
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