614
Practical MATLAB
® Applications for Engineers
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Solution to part (f)
Coefficients of the numerator of the trans. function
[butter/LPF/wc=1]
0 0 1
Coefficients of the denominator of the trans. function
[butter/LPF/wc=1]
1.0000 1.4142 1.0000
Transfer function:
1
----------------s^2 + 1.414 s + 1
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Solution to part (g)
Coefficients of the numerator of the transf. function
[butter/wc=2rad/sec]
4
Coefficients of the denominator of the transf. function
[butter/wc=2rad/sec]
1.0000 2.8284 4.0000
Transfer function:
4
----------------s^2 + 2.828 s + 4
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FIGURE 6.38
Plots of H(w) of Example 6.3 with R = L = C = 1.
1.4
0
Ϫ20
Ϫ40
Ϫ60
Ϫ80
Ϫ100
Ϫ120
Ϫ140
Ϫ160
Ϫ180
1.2
0.8
Magnitude
Angle in degrees
0.6
0.4
0.2
0
0
1
2
frequency in rad/sec
3
4
0
1
2
frequency in rad/sec
Phase of H(w) versus w
[for RϭLϭCϭ1]
Magnitude of H(w) versus w
[or RϭLϭCϭ1]
3
4
1
CRC_47760_CH006.indd 614
CRC_47760_CH006.indd 614
7/23/2008 2:26:46 PM
7/23/2008 2:26:46 PM