Low-Pass
8-Pole
Appendix A
Butterworth
Theoretical Transfer Characteristics
1
Frequency Response
0
-20
-40
-60
-80
-100
f/fc
Amp
(dB)
Phase
(deg)
Delay
(sec)
(Hz)
0.00
0.10
0.20
0.30
0.40
0.50
0.00
0.00
0.00
0.00
0.00
0.00
0.00
-29.4
-59.0
-89.1
-120
-152
.816
.819
.828
.843
.867
.903
0.60
0.70
0.80
0.85
0.90
-0.001
-0.014
-0.121
-0.311
-0.738
-185
-221
-261
-283
-307
.956
1.04
1.19
1.29
1.40
2
2
3 4 5 6 7
0.1
3 4 5 6 78 1.0
10.0
Normalized Frequency(f/fc)
0.95
1.00
1.10
1.20
1.30
-1.58
-3.01
-7.48
-12.9
-18.2
-333
-360
-408
-445
-472
1.48
1.46
1.17
.873
.672
Delay (Normalized)
2.0
1.0
0.0
1.40
1.50
1.60
1.70
1.80
-23.4
-28.2
-32.7
-36.9
-40.8
-494
-511
-526
-539
-550
.540
.448
.380
.328
.287
1.90
2.00
2.25
2.50
2.75
-44.6
-48.2
-56.3
-63.7
-70.3
-560
-568
-586
-600
-611
.253
.226
.174
.139
.113
0.15 2
3
4
1.5
0.1
5 6 7 8 91.0
3.00
3.25
3.50
4.00
5.00
-76.3
-81.9
-87.1
-96.3
-112
-621
-629
-635
-646
-661
.094
.080
.069
.052
.033
Normalized Time (1/f sec)
Step Response
6.00
7.00
8.00
9.00
10.0
-125
-135
-144
-153
-160
-671
-678
-683
-687
-691
.023
.017
.013
.010
.008
1.2
1.0
0.8
0.6
0.4
0.2
-0.0
1.Normalized Group Delay:
The above delay data is normalized to a corner frequency
of 1.0Hz.The actual delay is the normalized delay divided
by the actual corner frequency (fc).
0
1
2
3
4
5
Normalized Time (1/f sec)
Normalized Delay
Actual Delay =
Actual Corner Frequency (fc) in Hz
9
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