Why do I get an error on line 17?

clc
deviation = (1) .^ 0.5;
n = deviation .* randn(100000, 1); % noise
t = [-5: 0.01: 4.99]; % time 
p = 5 .* sin(20 .* pi .* t + (pi / 4)); % pulse p(t)
T = (2 * 1500) / 1000;
t2 = t - T;
p2 = 5 * sin(20 .* pi .* t2 + (pi / 4));
r = p2 + n;
x = randn(length(t), 1);
i = (t - T); 
y = linfilt(x, i, length(t));

figure(1);
subplot(3, 1, 1);
plot(t, p);
title('Plot 4a: Pulse p(t)'); % pulse p(t)
xlabel('Time');
ylabel('Amplitude');
grid;

subplot(3, 1, 2);
plot(t2, r);
title('Plot 4b: Received Signal r(t)'); % received signal r(t)
xlabel('Time');
ylabel('Amplitude');
axis([-5 4.99 min(y) max(y)]);
grid;

[C, tau] = xcorr(r,p); % cross-correlation R_rp(tau)
subplot(3, 1, 3);
plot(tau, C);
title('Plot 3c: Cross-Correlation R_rp(tau)');
grid;

[Walter Roberson]

We do not know which is line 17. Also, linfit() is not a MATLAB routine. There are several linfit() in the File Exchange, but we would not know which one of those you are using.

[KSSV]

?What is this function linfilt?