4-9
4 Making Measurements
The amplitude error caused by the filter can be determined from
The phase frequency response of the filter is shown in
Figure 4.4: Amplitude error of a 3rd order Bessel low pass filter in the passband
Figure 4.5: Phase frequency response of a 3rd order Bessel low pass filter in the passband
- 3 0
- 2 5
- 2 0
- 1 5
- 1 0
- 5
0
0 . 0
0 . 1
0 . 2
0 . 3
0 . 4
0 . 5
0 . 6
0 . 7
0 . 8
0 . 9
1 . 0
A m p l i t u d e e r r o r / %
f
f
C
- 1 0 0
- 8 0
- 6 0
- 4 0
- 2 0
0
0 . 0
0 . 2
0 . 4
0 . 6
0 . 8
1 . 0
P h a s e / d e g r e e s
f
f
C
