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Design of fir filters using windowing technique

Respected Sir / Madam I am developing code for fir filters using windowing technique. During the check process I am not fining any difference for a with in the allowable band and out of the band frequencies. I am posting the code as well.I am failing to interpret the output spectrum. Your help will be priceless. Yours sincerely T.V.Chandra Shekar

clc; clear; close; omegap = 1200; omegas = 1700; fs = 8000; rp = 0.01; rs = 0.02; wp = omegap/fs; ws = omegas/fs; N = ((-20*log10(sqrt(rp*rs)))-13)/(14.6*((omegas - omegap)/fs)); if (modulo(N,2)~=0) then N1 = N; N = N1-1; else N1 = N + 1; end disp(N); [wft,hm,fr]=wfir('lp',floor(N1),[wp],"re",[0 0]); disp(wft); subplot(2,1,1); plot(fr,hm);xgrid(color("green")); a = gca();a.x_location = "origin";a.y_location = "origin"; xtitle('Rectangular Window','f Frequecy','Magnitude'); den = [zeros(1,(length(wft)-1)) 1]; numpol = poly(wft,'z','coeff'); denpol = poly(den,'z','coeff'); firtff = syslin('d',numpol,denpol); n = 0:1023; x = 2*sin(2*%pi*2900*n/fs); y = flts(x,firtff); Y = abs(fft(y)); f = (0:1023)*fs/1024; subplot(2,1,2); plot2d(f,Y);xgrid(color("green")); xtitle('Magnitude Spectrum Of Output','Frequency f','Magnitude');

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