I am trying to design a digital butterworth filter for the given specifications.. code is posted below..
rp=3; rs=15; FS=1; wp=0.5*pi; ws=0.75*pi; pwp=2*FS*tan(wp/2); pws=2*FS*tan(ws/2); [n,wn]=buttord(pwp,pws,rp,rs,'s') [b,a]=butter(n,wn,'s'); [bn,an]=bilinear(b,a,FS);%error freqz(bn,an,512,FS);
My question is ,if i design a filter manually i am getting different values for 'bn' and 'an'.. but matlab gives different answer.. can anybody help me...?