
Low-Pass
4-Pole
Bessel
Appendix A
2 
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Normalized Frequency(f/fc)
A
Normalized Time (1/f sec)
D
Normalized Time (1/f sec)
S
Frequency Response
Delay 
(Normalized)
Step Response
0.1
1.0
10.0
2
3 4 5 678
2
3 4 5 67
-100
-80
-60
-40
-20
0
0.1
1.0
2
3
4
5 6 7 8 9
0.0
0.5
1.0
1.5
0.15
0
1
2
3
4
5
-0.0
-0.2
0.2
0.4
0.6
0.8
1.0
1.2
(sec)
.336
.336
.336
.336
.336
.336
Theoretical Transfer Characteristics
1
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.85
0.90
0.95
1.00
1.10
1.20
1.30
1.40
1.50
1.60
1.70
1.80
1.90
2.00
2.25
2.50
2.75
3.00
3.25
3.50
4.00
5.00
6.00
7.00
8.00
9.00
10.0
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).
Actual Delay  = 
Normalized Delay
Actual Corner Frequency (fc) in Hz
f/fc
(Hz)
Amp
(dB)
 0.00
-0.028
-0.111
-0.251
-0.448
-0.705
Phase
(deg)
 0.00
-12.1
-24.2
-36.3
-48.4
-60.6
-72.7
-84.8
-96.8
-103
-109
Delay
-48.1
-53.4
-58.0
-62.0
-65.7
-25.1
-27.6
-30.0
-34.4
-41.9
-12.2
-13.4
-16.5
-19.5
-22.4
-6.37
-7.42
-8.54
-9.71
-10.9
-2.69
-3.01
-3.71
-4.51
-5.39
-1.02
-1.41
-1.86
-2.11
-2.40
-315
-321
-326
-330
-333
-267
-275
-281
-291
-305
-212
-219
-235
-248
-259
-166
-177
-187
-195
-204
-115
-121
-133
-144
-156
.021
.016
.012
.009
.008
.089
.076
.065
.049
.031
.211
.194
.158
.129
.107
.295
.280
.263
.246
.228
.332
.330
.325
.318
.308
.336
.336
.335
.334
.333