Discrete Fourier Transform

Enter your input waveform here. Each data point should be on a separate line.


Input Waveform (Red) & Fourier Synthesis (Gray)
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Fourier Transform
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This page performs a discrete Fourier transform on real data and plots both the input waveform, the 'power' output, and the Fourier synthesis. Since the algorithm is not based on a fast Fourier transform (FFT), the number of input points can be any value (i.e., it is not limited to a power of two), but the speed is much slower. The output includes a listing of the input as a check, and the sine and cosine components for the transform. The 'power' is calculated as the square root of the sum of the squares of the sine and cosine component; these are the values plotted on the second graph. The Fourier synthesis is a back calculation of the waveform using the coefficients from the transform. Since the listings are delimited with tab characters, they can readily be exported into a spreadsheet.

Graphing uses the Canvas tag, which may not be available in some older browsers. The algorithm is in Javascript and can be viewed within the source of the page.

Jeffrey Clymer -- Debut July 4, 2011. Revision 3, July 9, 2011 -- Email -- Homepage