1. fs=8000;
2. t=0:1/fs:1;
3. x1=4*cos(2*pi*400*t);
4. x2=4*cos(2*pi*900*t+0.5*pi);
5. x3=5*cos(2*pi*400*t+0.25*pi);
6. xt=x1+x2+x3;
7.  
8. a=1;
9. bLP =[
10. -0.0012 -0.0025 -0.0045 -0.0068 -0.0073 -0.0030 0.0089 ...
11. 0.0297 0.0583 0.0907 0.1208 0.1422  0.1500 0.1422 ...
12. 0.1208 0.0907 0.0583 0.0297 0.0089 -0.0030 -0.0073 ...
13. -0.0068 -0.0045 -0.0025 -0.0012];
14. bBP =[
15. 0.0004 -0.0017 -0.0064 -0.0076 0.0073  0.0363 0.0458 ...
16. 0.0000 -0.0802 -0.1134 -0.0419 0.0860  0.1500 0.0860 ...
17. -0.0419 -0.1134 -0.0802 0.0000 0.0458  0.0363 0.0073 ...
18. -0.0076 -0.0064 -0.0017 0.0004 ];
19.  
20. figure(1)
21. freqz(bLP,a,512,fs);
22. figure(2)
23. freqz(bBP,a,512,fs);
24.  
25. y1=filter(bBP,a,xt);
26. Ak1=abs(fft(y1))/length(y1);
27. k1=0:1:length(y1)-1;
28. f1=k1*fs/length(y1);
29.  
30. y2=filter(bLP,a,xt);
31. Ak2=abs(fft(y2))/length(y2);
32. k2=0:1:length(y2)-1;
33. f2=k2*fs/length(y2);
34.  
35. Ak3=abs(fft(xt))/length(xt);
36. k3=0:1:length(xt)-1;
37. f3=k3*fs/length(xt);
38.  
39. figure(3)
40. subplot(3,1,1)
41. plot(f3,Ak3)
42. title('x(t)')
43. subplot(3,1,2)
44. plot(f1,Ak1)
45. title('band pass untuk y1')
46. subplot(3,1,3)
47. plot(f2,Ak2)
48. title('low pass untuk y2')