MATLAB cod for Frequency Modulation

Aim: Write MATLAB code to get the Frequency modulation 

Requirements: PC with MATLAB software

Program:

clc;
clear all;
close all;
fc=1000;
fs=10000;
f=200;
t=0:1/fs:((2/f)-(1/fs));
x=cos(2*pi*f*t);
kf=2*pi*(fc/fs)*(1/max(max(x)));
kf=kf*(f/fc);
opt=10*kf
y=modulate(x,fc,fs,'fm',opt);
subplot(3,1,1);
plot(x);
title('modulating signal');
subplot(3,1,2);
plot(y);
title('modulated fm signal');
x_recov=demod(y,fc,fs,'fm',opt);
subplot(3,1,3);
plot(x_recov);
title('original signal')

Output: