PRACTICAL MATLAB® FOR ENGINEERS PRACTICAL MATLAB

Alternating Current Analysis 281

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

0

0.5

1

1.5

Magnitude and phase of Z(w)

w (rad/sec)

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

w (rad/sec)

magnitude

− 200

− 150

− 100

− 50

0

phase in degrees

FIGURE 3.61

Plots for the circuit of Figure 3.59.

% Script file: circ _ Fig _ 360

echo on;

w = 7500:50:9500;

R = 1000;

L = 30e-3;

C = 0.47e-6;

num = [R 1/C R/(L*C)];

den = [1 0 1/(L*C)];

ZW = freqs(num, den, w);

subplot(2, 1, 1);

plot(w, abs(ZW));

grid on;

title(‘Magnitude and phase of Z(w)’);

xlabel(‘w(rad/sec)’);

ylabel(‘magnitude’);

subplot(2, 1, 2);

plot(w, angle(ZW)*180/pi);

xlabel(‘w(rad/sec)’);

ylabel(‘phase in degrees’);

grid on; % Figure 3.62