PRACTICAL MATLAB® FOR ENGINEERS PRACTICAL MATLAB

510 Practical MATLAB® Applications for Engineers

figure(6)

W=linspace(-2*pi,2*pi,100);

DTFT _ f1=1./(1-0.3*exp(-j.*W));

DTFT _ f2=1./(1-0.9*exp(-j.*W));

subplot (2,1,1)

plot (W,abs(DTFT _ f1));title(‘ DTFT[f1(n)]=1./(1-0.3*exp(-j.*W))’);

xlabel (‘frequency W ’), ylabel(‘Magnitude’)

subplot (2,1,2)

plot (W,angle(DTFT _ f1));

xlabel (‘frequency W’), ylabel(‘Phase angle in rad.’)

figure(7)

subplot(2,1,1)

plot(W,abs(DTFT _ f2));title(‘ DTFT[f2(n)]=1./(1-0.9*exp(-j.*W))’);

xlabel(‘frequency W ’), ylabel(‘Magnitude’)

subplot(2,1,2)

plot(W,angle(DTFT _ f2));

xlabel(‘frequency W ’), ylabel(‘Phase angle in rad.’)

The script fi le DTFT_properties is executed and the results are shown in Figures 5.21

through 5.27.

0

0

0.2

0.4

0.6

0.8

Amplitude of f1(n)

1

− 4 − 2 246810

f1(n) versus n

time index n

0

0

0.2

0.4

0.6

0.8

Amplitude of f2(n)

1

− 4 − 2 246810

f2(n) versus n

time index n

FIGURE 5.21
Discrete plots of f 1 (n) and f 2 (n) of Example 5.2.