Hello, I have to design a bandstop fir filter for a college project using hamming window with passband frequencys of 0.15 and 0.3 and apply it to a signal x = sin(2*pi*0.2*t) + sin(2*pi*0.1*t), 0<t<128. So far I wrote this:
fs = 10;
fp1 = 0.15;
fp2 = 0.3;
f1 = 0.2;
f2 = 0.1;
t = 128;
n = 0:1/fs:t;
x = sin(2*pi*f1*n) + sin(2*pi*f2*n);
Wn=[fp1 fp2];
Ham = fir1(30, Wn, 'stop');
[H,w] = freqz(Ham);
y = filter(Ham,1,x);
dB = mag2db(abs(H));
figure(1)
plot(w/pi, dB);
xlabel('Frequency');
ylabel('Magnitude (dB)');
figure(2)
plot(n, y);
title("Output y(n)",'fontsize',14);
xlabel('n');
ylabel('Y(n)');
However, my output signal y is almost the same as my input signal x, when I believe all that should be left is sin(2*pi*0.1*t). If I use bandstop function as "bandstop(x,Wn,fs)" the results are fine, but I cant replicate them using the upper method. If anyone knows what I am doing wrong I would appreciate any tips and advices.
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