The Math::FFT module provides an interface to various Fast Fourier Transform (FFT) routines of the C routine of fft4g.c, available at http://momonga.t.u-tokyo.ac.jp/~ooura/fft.html. The one-dimensional data sets, of size 2^n, are assumed to be sampled at a constant rate. The FFT methods available are - cdft: Complex Discrete Fourier Transform - rdft: Real Discrete Fourier Transform - ddct: Discrete Cosine Transform - ddst: Discrete Sine Transform - dfct: Cosine Transform of RDFT (Real Symmetric DFT) - dfst: Sine Transform of RDFT (Real Symmetric DFT) as well as their inverses. Also available are some methods to implement some common applications of FFTs for real data sets. These are - correl: Find the correlation between two data sets - convlv: Find the convolution of one data set with another - deconvlv: Find the deconvolution of one data set with another - spctrm: Find the power spectrum of a data set, including application of a windowing function and segmentation of the data. Finally, for convenience some common statistical methods are included for analyzing real data sets. These are - mean: Find the mean of a data set - stdev: Find the standard deviation of a data set - range: Find the minimum and maximum values of a data set - median: Find the median of a data set - rms: Find the root mean square of a data set The C code for the FFT routines of fft4g.c is copyrighted 1996-99 by Takuya OOURA. The file arrays.c included here to handle passing arrays to and from C comes from the PGPLOT module of Karl Glazebrook . The perl interface of the Math::FTT module is Copyright 2000,2005 by Randy Kobes , and may be distributed under the same terms as Perl itself.