M = 45; As = 60; 

n = [0:1:M-1];

beta = 0.1102*(As - 8.7)

%beta = 0.1102*(As - 8.7) + 0.3

w_kai = (kaiser(M, beta))'; wc1 = pi/3; wc2 = 2*pi/3;

hd = ideal_lp(wc1, M) + ideal_lp(pi, M) - ideal_lp(wc2, M);

h = hd .* w_kai;

[db, mag, pha, grd, w] = freqz_m(h, [1]);  

%Plot

figure('NumberTitle', 'off', 'Name', 'Exameple 7.11')

set(gcf,'Color','white'); 

subplot(2,2,1); stem(n, hd); axis([0 M-1 -0.2 0.8]); grid on;

xlabel('n'); ylabel('hd(n)'); title('Ideal Impulse Response');

subplot(2,2,2); stem(n, w_kai); axis([0 M-1 0 1.1]); grid on;

xlabel('n'); ylabel('w(n)'); title('Kaiser Window');

subplot(2,2,3); stem(n, h); axis([0 M-1 -0.2 0.8]); grid on;

xlabel('n'); ylabel('h(n)'); title('Actual Impulse Response');

subplot(2,2,4); plot(w/pi, db); axis([0 1 -80 10]); grid on;

xlabel('frequency in \pi units'); ylabel('Decibels'); title('Magnitude Response in dB');