Digital Signal Processing Reference
In-Depth Information
2,5
2,0
nonlinear "mirror"
1,5
1,0
linear "mirror"
0,5
0,0
-0,5
-1,0
-1,5
-2,0
-2,5
Sinus
Projection of sinus
-2,5
-2,0
-1,5
-1,0
-0,5
0,0
0,5
1,0
1, 5
2, 0
2,5
V
2,00
1,00
0,00
-1,00
-2,00
35.0
37.5
40.0
42.5
45.0
47.5
50.0
52.5
55.0
57.5
ms
2,50
2,25
2,00
1,75
1,50
1,25
1,00
0,75
0,50
0,25
0,00
1,0
0,9
0,8
0,7
0,6
0,5
0,4
0,3
0,2
0,1
0,0
0
2500
5000
7500
10000
Hz
Illustration 124:
Non-linear distortion of a sinusoidal oscillation
A new signal is created by projecting a sinusoidal oscillation at a non-linear characteristic curve. The
sinusoidal oscillation contains merely one frequency whereas the new signal contains several frequencies
in the spectrum (bottom spectrum).
The angle of incidence of each beam, however, is not equal to its angle of reflection. If
the characteristic curve is linear the proportions are maintained in the projection. If it is
non-linear the proportions are distorted. Illustration 124, bottom, shows a sinusoidal
oscillation which is transformed into an obtuse rectangular pulse.
While the sine contains just one frequency, the analysis of the obtuse rectangle shows that
there are several frequencies. It follows from that that non-linear characteristic curves
create distortions which in the frequency range also create additional frequencies, i.e. non-
linear distortions.
