How to choose Window Function?

[yolande_yj]

There are so many window function like retagular, Guass, Hamming, Hann...
So what is the criteria of choosing a proper window function?

 

[wwfhm2002]

some have better ripple, some have better main band (leakage is least), some have better stop band attenuation.

 

[Kral]

yolande_yj,
For a nice discussion of windows, see the following:
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h**p://www-nt.e-technik.uni-erlangen.de/WORLD/LNT/lehre/dsv/DSP_p0-591bw.pdf
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Window selection always involves a tradeoff between passband ripple and transition band steepness. The Kaiser window is convenient because it provides a continuum of ripple specifications by the selection of a single paramter. As ripple improves, transition steepnes gets worse, and vice-versa.
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Regards,
Kral