Tektronix DPO70000C/DX Series User Manual

Math setups FFT window characteristics
FFT w indow characteristics
Each FFT window is a trade-off between frequency resolution and magnitude accuracy. What you want to
measure and your source signal c haracteristics h el p determine which window to use. Use the following
guidelines t
o select the best window.
FFT window Characteris
tics
Best for m eas
uring
Rectangular
Best freque
ncy, worst magnitude
resolution. This is essentially the
same as no window.
Transients or bursts where the signal
levels befo
re and after the event are
nearly equal.
Equal-amplitude sine waves with
frequenci
es that are very close.
Hamming, Hanning
Better fre
quency, poorer magnitude
accuracy than Rectangular. Hamming
has slightly better frequency resolution
than Hann
ing.
Sine, peri
odic, and narrow-band
random noise.
Transients or bursts where the signal
levels be
fore and after the event are
significantly different.
Blackma
n-Harris
Best magnitude, worst frequency
resolution.
Predominantly single frequency
signals to look for higher order
harmoni
cs.
xxx
You can also determine the best window empirically by first selecting the Rectangula r window, and
then selecting (in the following order) the Hamming, Hanning, and Blackman-Harris windows until the
frequency components merge. Use the window just prior to where the frequencies emerge for the best
compromise between resolution and amplitude accuracy.
254 DSA/DPO70000D, MSO/DPO/DSA70000C, DPO7000C, and MSO/DPO5000 Series

Tektronix DPO70000C/DX Series Specifications

General

Brand	Tektronix
Model	DPO70000C/DX Series
Category	Test Equipment
Language	English