OWON SDS Series - Manual (Page 34)

5.Advanced User Guidebook
Type Characteristics Window
Rectangle
Best solution for frequency, worst for magnitude.
Best type for measuring the frequency spectrum of
nonrepetitive signals and measuring frequency
components near DC.
Recommend to use for:
 Transients or bursts, the signal level before and
after the event are nearly equal.
 Equal-amplitude sine waves with frequencies
those are very close.
 Broadband random noise with a relatively slow
varying spectrum.
Hamming
Better solution for magnitude than Rectangle, and
good for frequency as well. It has slightly better
frequency resolution than Hanning.
Recommend to use for:
 Sine, periodic and narrow band random noise.
 Transients or bursts where the signal levels
before and after the event are significantly
different.
Hanning
Good for magnitude, but poorer frequency
resolution than Hamming.
Recommend to use for:
 Sine, periodic and narrow band random noise.
 Transients or bursts where the signal levels
before and after the event are significantly
different.
Blackman
Best solution for magnitude, worst for frequency.
Recommend to use for:
 Single frequency waveforms, to find higher
order harmonics.
Figure 5-10 is a examples for measuring sine wave with a frequency of 1kHz under the
selection of four different windows for FFT:
29