close all, clear all, clc
fs = 5E3;
fs2 = fs/2;
fc = 1000;
fn = fc/fs2;
N = 5;
num = fir1(N, fn, boxcar(N + 1));
[H, w] = freqz(num, 1);
subplot(2,1,1), plot(w/(2*pi)*fs, abs(H)), grid
subplot(2,1,2), plot(w/(2*pi)*fs, unwrap(angle(H))), grid