Wednesday, April 3, 2013

Frequency Modulation using MATLAB


%Frequency modulation
%fm=100;Am=5;
%fc=3000; Ac=5;

clear all;
close all;
clc;
fm=input('enter msg signal frequency fm=');
Am=input('enter msg signal amplitude Am=');
fc=input('enter carrier signal frequency fc=');
Ac=input('enter carrier signal amplitude Ac=');
fs=100000;
t=0:1/fs:0.05;
m=Am*cos(2*pi*fm*t);
c=Ac*cos(2*pi*fc*t);
subplot(311);
plot(m);
title('input msg signal','fontsize',14);
xlabel('--->time in 10us','fontsize',11);
ylabel('--->Amplitude in Volts','fontsize',11);
subplot(312);
plot(c,'r');
title('input carrier signal','fontsize',14);
xlabel('--->time in 10us','fontsize',11);
ylabel('--->Amplitude in Volts','fontsize',11);
B=(500*Am)/fm; % kf=500 < fc
s=Ac*cos(2*pi*fc*t + (B*sin(2*pi*fm*t)));
subplot(313);
plot(s);

title('output FM signal','fontsize',14);
xlabel('--->time in 10us','fontsize',11);
ylabel('--->Amplitude in Volts','fontsize',11);


OUTPUT: