604
Practical MATLAB
® Applications for Engineers
Example 6.2
Given the fi rst-order analog HPF shown in the circuit diagram of Figure 6.31, evaluate
by hand the following:
a. The transfer function H(w) = V o (w)/V i (w)
b. Obtain expressions for ͉H(w)͉ and ∠H(w)
Create the script fi le HP_fi lter_analysis that returns the following plots:
c. ͉H(f)͉ versus f and ∠H(f ) versus f using the MATLAB function freqs
d. ͉H(f)͉ dB versus f and ∠H(f) versus f using a semilog scale and the MATLAB function
freqs
e. Bode of ͉H(w)͉ and ∠H(w) over the range −5 * (1/(R * C)) ≤ w ≤ 5 * (1/(R * C))
f. Bode of ͉H(w)͉ and ∠H(w) with no argument (w)
g. ͉H(f)͉ versus f
∠H(w) versus f
͉H(f)͉ dB versus f (semilog scale)
∠H(f) versus f (semilog scale)
using standard circuit techniques.
FIGURE 6.30
Plots of ͉H(f)͉, ∠H(f), ͉H(f)͉ dB , and ∠H(f ) using standard circuit techniques of Example 6.1.
0
mag. versus freq.
mag. (in db) versus freq.
phase versus freq.
phase versus freq.
frequency in Hrz
frequency in Hrz
0
0.2
magnitude
magnitude (db)
0.4
0.6
0.8
1
5
Ϫ5
5
Ϫ5
Ϫ15
Ϫ10
Ϫ5
0
phase (in degrees)
phase (in degrees)
Ϫ80
Ϫ60
Ϫ40
Ϫ20
0
Ϫ100
Ϫ50
0
50
100
0
10
4
ϫ10
4
ϫ10
4
10
6
10
4
10
2
10
6
CRC_47760_CH006.indd 604
CRC_47760_CH006.indd 604
7/23/2008 2:26:44 PM
7/23/2008 2:26:44 PM