close all
k = input('Number of frequency points = ');
w = 0:pi/k:pi;
alpha=0.3
num=((1-alpha)/2)*[1 1]
den=[1 -alpha]
hlp=freqz(num,den,w)
num1=((1+alpha)/2)*[1 -1]
den1=[1 -alpha]
hhp=freqz(num1,den1,w)
figure
subplot(2,1,1)
plot(w/pi, abs(hlp),'k','LineWidth', 2);hold on
grid on;
xlabel('\omega/\pi', 'FontSize', 12, 'FontWeight', 'Bold')
ylabel('Amplitude', 'FontSize', 12, 'FontWeight', 'Bold')
title('|H(\omega)|', 'FontSize', 12, 'FontWeight', 'Bold')
set(gca, 'FontSize', 14, 'FontWeight', 'Bold')
plot(w/pi, abs(hhp), 'LineWidth', 2);hold on
grid on;
xlabel('\omega/\pi', 'FontSize', 12, 'FontWeight', 'Bold')
ylabel('Amplitude', 'FontSize', 12, 'FontWeight', 'Bold')
title('|H(\omega)|', 'FontSize', 12, 'FontWeight', 'Bold')
set(gca, 'FontSize', 14, 'FontWeight', 'Bold')
plot(w/pi, abs(all_pass),'r', 'LineWidth', 2);hold on
grid on;
xlabel('\omega/\pi', 'FontSize', 12, 'FontWeight', 'Bold')
ylabel('Amplitude', 'FontSize', 12, 'FontWeight', 'Bold')
title('|H(\omega)|', 'FontSize', 12, 'FontWeight', 'Bold')
set(gca, 'FontSize', 14, 'FontWeight', 'Bold')
legend ('low pass','high pass','all pass','Location', 'Northwest')
set(legend,'FontSize',7);
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