# bandpass implementing with DWT in matlab

In matlab help in find the implementation of bandpass as following

  fs=8800;
n = 0:159;
x =sin(n)+sin(n)*pi; % whatever here say it music
d = fdesign.bandpass('Fst1,Fp1,Fp2,Fst2,Ast1,Ap,Ast2',1/4,3/8,5/8,6/8,2800 /fs,200,3000/fs);
Hd = design(d,'equiripple');
%Apply the filter to the discrete-time signal.
y = filter(Hd,x);
freq = 0:(2*pi)/length(x):pi;

-> xdft = fft(x);
->ydft = fft(y);

plot(freq,abs(xdft(1:length(x)/2+1)));
hold on;
plot(freq,abs(ydft(1:length(x)/2+1)),'r','linewidth',2);
legend('Original Signal','Bandpass Signal');
figure(2)
plot(xdft(1:length(x)/2+1),'r');
hold on
plot(ydft(1:length(y)/2+1));
legend('Original Signal','Bandpass Signal');


as you see the arrows refer to the dft function to make transform I want to make use the dwt function to transform to freqency domain and make it seen to me so I can easily use bandpass filter or if condition

thank you for helping

• Your question as it stands is not very clear. What's your signal? Where's the music? What else is in the signal? Why do you think that by replacing the FFT by a DWT you can remove music from a signal? (If that's what you want to do ...). I suggest to edit your question to make it a lot clearer in order to increase the chance of getting useful answers. – Matt L. May 16 '13 at 9:55