close all, clear all, clc
load c3k2
N = 8192;
Fs = 2048;
Fs2 = Fs/2;
%soundsc(y, Fs)
Y = fft(y, N);
N2 = N/2;
m = 1:N2;
f = linspace(0, Fs2, N2);
magY = abs(Y(m));
figure(1)
subplot(2,1,1), plot(f, magY)
Rp = 0.1;
Rs = 30;
fs = [345 355];
fp = [340 360];
Wp = fp/Fs2;
Ws = fs/Fs2;
[Nf, Wn] = ellipord(Wp, Ws, Rp, Rs);
[B, A] = ellip(Nf, Rp, Rs, Wn, 'stop');
yf = filter(B, A, y);
YF = fft(yf, N);
magYF = abs(YF(m));
subplot(2,1,2), plot(f, magYF)
%soundsc(yf, Fs)
figure(2)
[H, w] = freqz(B, A);
figure(2)
plot(w/pi*Fs2, abs(H))