Setting up Compax3 C3I22T11
256 192-120114 N5 C3I22T11 June 2008
Leak effect and windowing
If frequencies not corresponding to the frequency resolution are present in the ana-
lyzed spectrum, the so-called leak effect can be caused.
Display of the leak effect with the aid of a 16 point discrete Fourier transformation
Complete oscillation period in the scanning
period
f
0
Envelope without leak effect
Non complete oscillation period in the scanning
period
f
0
Envelope with leak effect
Sine at 200Hz without windowing
Consequence of the leak effect shown at the example of a sine signal.
(fA=4000Hz; N=500; => Δf=8Hz
f0=200Hz = 25*Δf frequency corresponds to the frequency-resolution
The sine frequency is exactly on a multiple of the frequency resolution (200Hz /
8Hz=25). The spectre is clearly separated and there are no leak effects visible.
To Next Page
Loading...
