Digital Signal Processing Tutorial 5

1.

     clc;

clear all;

close all;

w = linspace(0,10,1024)

[b1 a1] = cheby1(3,0.5,5,'s')

[b3 a2] = cheby1(5,0.5,5,'s')

[b2 a3] = cheby1(10,0.5,5,'s')

H1 = freqs(b1,a1,w)

H2 = freqs(b2,a2,w)

H3 = freqs(b3,a3,w)

H1 = abs(H1)/max(abs(H1))

H2 = abs(H2)/max(abs(H2))

H3 = abs(H3)/max(abs(H3))

plot(w,abs(H1))

grid;hold on

plot(w,abs(H2),'r')

plot(w,abs(H3),'g')

legend('N=3','N=5','N=10')

2.

1. clc;

clear all;

close all;

[N Wn] = buttord(0.7264,1.3764,2,50,'s')

[b a] = butter(N,Wn,'s')

[H W] = freqs(b,a)

subplot(2,1,1)

plot(W,abs(H))

grid

axis([0 2 0 1.2])

xlabel('Frequency,rad/s')

ylabel('Magnitude')

title('Analog Filter H(\Omega)')

subplot(2,1,2)

plot(W,20*log10(abs(H)))

axis([0 2 0 1])

grid

xlabel('Frequency,rad/s')

title('Analog Filter H(\Omega)Gain in dB')

ylabel('Gain in dB')

axis([0 2 -100 0])