Fast Fourier Transforms
Reference
3Ć52
Rectangular Window
0 dB
-20
-40
-50
Hanning Window
0 dB
-20
-40
-60
-80
Hamming Window
0 dB
-20
-40
-60
BlackmanĆHarris
Window
0 dB
-20
-40
-60
-80
-100
-101
FFT Window Type Bandpass Filter
0.89
Ć3 dB Bandwidth Highest Side Lobe
1.28
1.28
1.28
Ć13 dB
-32 dB
-43 dB
-94 dB
Figure 3Ć28:ăFFT Windows and Bandpass Characteristics
Care should be taken when using bell shaped widows to be sure that the
most interesting parts of the signal in the time domain record are positioned
in the center region of the window so that the tapering does not cause
severe errors.
See Waveform Differentiation, on page 3Ć139.
See Waveform Integration, on page 3Ć143.
See Waveform Math, on page 3Ć148.
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