Scicos Block
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Fast Fourier Transform block





That block computes a direct or backward Fast Fourier Transform. Regular inputs/outputs are the real and imaginary part of a complex number. They are vectorial.

The parameter Mode details which algorithms are used to compute the FFT.

If Mode=0 the interfacing function will automatically choose between the fft842 and dfftmx algorithms. The first are more powerful for computational time but only work for size of vectors with 2 power and for size less than 2^15. The second algorithm (dfftmx) can work for any size of vector but is more slow. If the size of the input vector is a 2 power and less than 2^15 fft842 will be used else this is dfftmx.

Mode=1 is to always use dfftmx.

If the 'Modnum' toolbox have been build with the FFTW library the block will automatically use that library in any case.

Dialog box


Default properties

Interfacing function

Computational function

See also


A. Layec


Signal Processing with Scilab. Available : signal.pdf

FFTW. Available : FFTW web site