clear;
Fs = 8000;
N = 800;
delayS = 7;
[B,A] = cheby2(4,20,[0.04 0.5]);
Hd = dfilt.df2t(B,A);
H = filter(Hd,[zeros(1,delayS) log(0.99*rand(1,N-delayS)+0.01).*sign(randn(1,N-delayS)).*exp(-0.01*(1:N-delayS))]);
H = H/norm(H);
t = 1/Fs:1/Fs:N/Fs;
plot(t,H,'b');
xlabel('Time [sec]');
ylabel('Coefficient value');
title('True Secondary Path Impulse Response');
hold;