Discrete Fast Fourier Transform

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

Output

Input Waveform
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Output
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This page performs a discrete fast Fourier transform on real data and plots both the input waveform and the 'power' output. Since the algorithm is based on a fast Fourier transform (FFT), the number of input points is limited to a power of two. Points beyond a power of two are discarded; for example, if 100 points are input, only 64 (2^6) points are used. 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. 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 -- July 4, 2011. Revision 2, July 6, 2011 -- Email -- Homepage

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