4.Advanced User Guidebook
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Blackman
Best solution for magnitude, worst for
frequency.
Recommend to use for:
Single frequency waveforms, to find higher
order harmonics.
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.
Kaiser
The frequency resolution when using the
Kaiser window is fair; the spectral leakage and
amplitude accuracy are both good.
The Kaiser window is best used when
frequencies are very close to the same value
but have widely differing amplitudes (the side
lobe level and shape factor are closest to the
traditional Gaussian RBW). This window is also
good for random signals.
Bartlett
The Bartlett window is a slightly narrower
variant of the triangular window, with zero
weight at both ends.
Notes for using FFT
Use the default
dB
scale for details of multiple frequencies, even if they have
very different amplitudes. Use the
Vrms
scale to compare frequencies.
DC component or offset can cause incorrect magnitude values of FFT
waveform. To minimize the DC component, choose AC Coupling on the source
signal.
To reduce random noise and aliased components in repetitive or single-shot
events, set the oscilloscope acquisition mode to average.
What is Nyquist frequency?
The Nyquist frequency is the highest frequency that any real-time digitizing
oscilloscope can acquire without aliasing. This frequency is half of the sample rate.
Frequencies above the Nyquist frequency will be under sampled, which causes
