Frequency Modulation Using MATLAB

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frequency modulation Matlab

Frequency Modulation:-

In telecommunications and signal processing, frequency modulation (FM) is the encoding of information in a carrier wave by varying the instantaneous frequency of the wave.

In analog frequency modulation, such as FM radio broadcasting of an audio signal representing voice or music, the instantaneous frequency deviation, the difference between the frequency of the carrier and its center frequency, is proportional to the modulating signal.

Frequency modulation is widely used for FM radio broadcasting. It is also used in telemetry, radar, seismic prospecting, and monitoring newborns for seizures via EEG, two-way radio systems, music synthesis, magnetic tape-recording systems and some video-transmission systems. In radio transmission, an advantage of frequency modulation is that it has a larger signal-to-noise ratio and therefore rejects radio frequency interference better than an equal power amplitude modulation (AM) signal. For this reason, most music is broadcast over FM radio.

Input:-

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%Frequency modulation
%fm=100;Am=5;
%fc=3000; Ac=5;
<b>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('---&gt;time in 10us','fontsize',11);
ylabel('---&gt;Amplitude in Volts','fontsize',11);
subplot(312);
plot(c,'r');
title('input carrier signal','fontsize',14);
xlabel('---&gt;time in 10us','fontsize',11);
ylabel('---&gt;Amplitude in Volts','fontsize',11);
B=(500*Am)/fm; % kf=500 &lt; fc
s=Ac*cos(2*pi*fc*t + (B*sin(2*pi*fm*t)));
subplot(313);
plot(s);</b>
<b>title('output FM signal','fontsize',14);
xlabel('---&gt;time in 10us','fontsize',11);
ylabel('---&gt;Amplitude in Volts','fontsize',11);</b>

Output:-

frequency modulation

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