%Low Pass Filter
clear all;
close all;

ts=0.001;
Q=tf([1],[0.04,1]);   %Low Freq Signal Filter
Qz=c2d(Q,ts,'tucsin');
[num,den]=tfdata(Qz,'v');

y_1=0;y_2=0;
r_1=0;r_2=0;
for k=1:1:5000
time(k)=k*ts;

%Input Signal with disturbance
D(k)=0.10*sin(100*2*pi*k*ts);  %Disturbance signal
rin(k)=D(k)+0.50*sin(0.2*2*pi*k*ts); %Input Signal

yout(k)=-den(2)*y_1+num(1)*rin(k)+num(2)*r_1;

y_2=y_1;y_1=yout(k);
r_2=r_1;r_1=rin(k);
end
figure(1);bode(Q);
figure(2);
subplot(211);
plot(time,rin,'r');
xlabel('time(s)');ylabel('rin');
subplot(212);
plot(time,yout,'b');
xlabel('time(s)');ylabel('yout');