TECH ARTICLE
Figure 1: An FFT of a 300-kHz square wave.
Window Type
Applications & Limitations
Rectangular
Normally used when the signal is transient – completely contained in the time-domain window – or known to have a fundamental frequency component that is an integer multiple of the fundamental frequency of the window. Signals other than these types will show varying amounts of spectral leakage and scallop loss, corrected by selecting another type of window.
Hanning (Von Hann)
Reduce leakage and improve amplitude accuracy. However, frequency resolution is also reduced.
Hamming
Reduce leakage and improve amplitude accuracy. However, frequency resolution is also reduced.
Flat Top
The window provides excellent amplitude accuracy with moderate reduction of leakage, but also at the loss of frequency resolution.
Blackman–Harris
It reduces the leakage to a minimum, but again along with reduced frequency resolution. Table 1: FFT window types and their characteristics.
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