FREQUENCY MODULATION (FM)

PROGRAM:
clc;
clf;
clear;
close all;

fs = 1000;
t = (0:2*fs+1)'/fs;
fm = 1;
fc = 20;
sm = cos(2*pi*fm*t);
x =  cos(2*pi*fc*t + 10 * sm);

z=demod(x,fc,fs,'fm');
subplot(2,1,1);
plot(t,sm,t,x);
subplot(2,1,2);
plot(t,z);

PLOT: