RIGOL DS1000B - Manual (Page 48)

RIGOL
User’s Guide for DS1000B series 2-18
2. Selecting an FFT Window
DS1000B series oscilloscope provides four FFT windows. Each window is a
trade-off between frequency resolution and amplitude accuracy. It depends on
the desired measurement and the source signals characteristics to determine
the window to use. Use the following guidelines to select the best window.
DS1000B provides four FFT functions with different features, which are needed
to be selected according to measuring waveform.
Table 2-10 FFT Windows
Window Features Best for measuring
Rectangle
Best frequency resolution
and worst amplitude
accuracy.
This is essentially
the same as no window.
Transients or bursts, the signal
levels before and after the event
are nearly equal.
Equal-amplitude sine waves with
fixed frequencies.
Broadband random noise with a
relatively slow varying spectrum.
Hanning
Better frequency
resolution, poorer
amplitude accuracy than
Rectangular.
Sine, periodic, and narrow-band
random noise.
Hamming
Hamming has slightly
better frequency
resolution than Hanning. Transients or bursts where the
signal levels before and after the
events are significantly different.
Blackman
Best amplitude accuracy,
worst frequency
resolution.
Single frequency waveforms, to
find higher order harmonics.