PRACTICAL MATLAB® FOR ENGINEERS PRACTICAL MATLAB

600 Practical MATLAB® Applications for Engineers

g. Repeat 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.

ANALYTICAL Solution

Part (a)

Hw Vw

Vw

jwC

jwC

R

RC

jw

RC

o

i

() ()

()

*

* *





1

1

1

1

Part (b)

Hw RC

w

RC

()




1

2 1 2

*

*









∠H(w) = tan−^1 (w * R * C)

MATLAB Solution

% Script File: LP _ filter _ analysis

R=1e3/(2*pi);

C=.1e-6;

a=1/(R*C);

w =-5*a:10000:5*a;

num=a;

den=[1 a];

Hlp = freqs(num,den,w);

figure(1);

subplot(2,1,1);

plot(w/(2*pi),abs(Hlp));

xlabel (‘frequency in Hrz’);

ylabel (‘magnitude’);

title(‘Magnitude of H(f) vs. frequency’);

FIGURE 6.25
Circuit diagram of Example 6.1.

R = 1/(2*π) KΩ

Vi(w) C = 1 μF Vo(w)