Owon VDS1022l User Manual page 29

Good for magnitude, but poorer frequency resolution than Hamming.
Recommend to use for:
Hanning
 Sine, periodic and narrow band random noise.
 Transients or bursts where the signal levels before and after the event are significantly different.
The figures below are examples for measuring sine wave with a frequency of 1 kHz under the selection of four different windows for FFT:
Figure: Hamming window
Figure: Rectangle window
Figure: Blackman window
Figure: Hanning window
Notes for using FFT
 Select "Scale" to magnify the FFT waveform if necessary.
 Use the default dB scale for details of multiple frequencies, even if they have very different amplitudes. Use the Vrms scale to compare
frequencies.
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