PRACTICAL MATLAB® FOR ENGINEERS PRACTICAL MATLAB

654 Practical MATLAB® Applications for Engineers

FIGURE 6.78
Filter’s plot of part (c) of Example 6.20.

1.4 200

150

100

50

 50

 100

 150

 200

0

1.2

0.8

Magnitude

Angle in degrees

0.6

0.4

0.2

0

0 0.5

frequency W in rad

Mag. of BPF using remez/order
 8 Phase of BPF using remez/order
 8

1 0 0.5

frequency W in rad

1

1

For each of the fi lters obtain the magnitude and phase plots.

The solution is given by the script fi le review_ FIR_LPF as follows:

MATLAB Solution

% Script file : review _ FIR _ LPF

% Design of FIR using remez

f = linspace(0,1,10);

mag = [ones(1,3) .707 zeros(1,6)];

Pz = remez(25,f,mag);

Qz =1;

Hremez = freqz(Pz,Qz);

omega = 0:1/512:511/512;

figure(1)

subplot(2,1,1)

plot(omega,abs(Hremez))

xlabel(‘frequency in rad’)

ylabel(‘magnitude’)

title(‘Mag./FIR using remez’)

grid on;

subplot(2,1,2)

plot(o m e ga,u nw rap(a n gle(H r e m ez)))

xlabel(‘frequency in rad’)

ylabel(‘phase’)

title(‘Phase/FIR using remez’)

grid on;

% Design of FIR using fir1/Hamming window

Pz1 = fir1(25,0.3);

win = hamming(26);

Pz1= Pz1.*win’;

Hfir1= freqz(Pz1,1);