Digital Signal Processing Reference
In-Depth Information
Time domain
1,00
0,75
0,50
0,25
0,00
-0,25
4,0
3,5
3,0
2,5
2,0
1,5
1,0
0,5
0,0
4,0
3,5
3,0
2,5
2,0
1,5
1,0
0,5
0,0
-0,5
-1,0
1,00
0,75
0,50
0,25
0,00
1,00
0,75
0,50
0,25
0,00
-0,25
4,0
3,5
3,0
2,5
2,0
1,5
1,0
0,5
0,0
-0,5
-1,0
Rectangle window
50
100
150
200
250
300
350
400
450
500
550
600
650
700
750
800
850
900
950
ms
Frequency domain
0,15
0,11
0,07
0,04
0,00
0,40
0,30
0,20
0,10
0,00
0,02
0,01
0,01
0,01
0,00
0,50
0,38
0,25
0,13
0,00
0,20
0,15
0,10
0,05
0,00
0,02
0,01
0,01
0,01
0,00
25
50
75
100
Hz
Illustration 203:
Signal distortion as a result of signal windowing
In the case of longer signals the signal must be processed in segments. This gives rise to errors as shown in
Illustration 51. Using the example of the rectangular window we show once again how the spectrum can
be changed or distorted. Typical of rectangular windows is the “ripple effect” of the spectrum (bottom)
compared with the correct spectrum in the third series (bottom).
