update lab 4

load ctftmod.mat

% 4.6(a)

z = [dash dash dot dot]

% 4.6(b)

figure;

freqs(bf, af)

title('Frequency response of bf and af');

saveas(gcf, "plots/P4_6_b_out.png")

close

% 4.6(c)

ydash = lsim(bf, af, dash, t(1:length(dash)))

ydot = lsim(bf, af, dot, t(1:length(dot)))

figure;

subplot(2,1,1)

hold on;

plot(t(1:length(dash)), dash);

plot(t(1:length(dash)), ydash);

legend('dash', 'dash after lowpass filter', 'Location', 'northeast');

title('dash and dash after lowpass filter');

xlabel('t');

subplot(2,1,2)

hold on;

plot(t(1:length(dot)), dot);

plot(t(1:length(dot)), ydot);

title('dot and dot after lowpass filter');

legend('dot', 'dot after lowpass filter', 'Location', 'northeast');

xlabel('t');

saveas(gcf, 'plots/P4_6_c_out.png')

close

% 4.6(d)

y = dash .* cos(2*pi*f1*t(1:length(dash)))

yo = lsim(bf, af, y, t(1:length(y)))

figure;

subplot(2,1,1)

hold on;

plot(t(1:length(dash)), y);

title('y');

subplot(2,1,2)

plot(t(1:length(y)), yo);

title('After being filtered');

saveas(gcf, 'plots/P4_6_d_out.png')

% 4.6(e)

% 4.6(f)

% 4.6(g)

x1 = x .* sin(2*pi*f1*t(1:length(x)))

m1 = lsim(bf, af, x1, t(1:length(x1)))

x2 = x .* sin(2*pi*f2*t(1:length(x)))

m2 = lsim(bf, af, x2, t(1:length(x2)))

x3 = x .* cos(2*pi*f1*t(1:length(x)))

m3 = lsim(bf, af, x3, t(1:length(x3)))

figure;

subplot(3,1,1)

plot(t, m1);

title('m1');

xlabel('t');

subplot(3,1,2)

plot(t, m2);

title('m2');

xlabel('t');

subplot(3,1,3)

plot(t, m3);

title('m3');

xlabel('t');

saveas(gcf, "plots/P4_6_g_out.png")

close

% . _ _ . P

% . _ _ .