FFT Window Functions
The window type list for Perform FFT on Report are listed below.
|
Window Function |
Preferred Use |
|
Rectangular |
A low dynamic range function offering
good resolution for signals of comparable strength. Poor when signals
have very different amplitudes. w(n)=1 
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Tri |
A Bartlett window with the endpoints valued at zero. 
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Van Hann |
A moderate dynamic range function, designed for narrow band applications.
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Blackman |
A high dynamic range function, with lower resolution, designed for wide band applications.
where a0 =(1-a)/2; a1=1/2; a2=a/2
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Hamming |
A moderate dynamic range function, designed for narrow band applications. It minimizes the maximum sidelobe.
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Lanczos |
The Lanczos window offers a windowed form of the infinite sinc filter, providing the central lobe of a horizontally stretched sinc, sinc(x/a) for -a £ x £ a. 
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Weber |
Decomposes functions into Laguerre series (orthogonal polynomials), and then uses FFT to evaluate the transform; for more details, see H. Weber, "Numerical Computation of the Fourier Transform Using Laguerre Functions and the Fast Fourier Transform", Numer. Math., Vol. 36, pp. 197--209 (1981). |
|
Welch |
This approach applies a parabola-shaped window to the frequency domain data. It is based on the Bartlett method but splits the signal into overlapping segments, which are then windowed. The intent is to balance the influence of data in the center of the function. |
