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