Amplitude Modulation – Matlab Tutorial (Amplitude modulation in Matlab with Code) 2016

Matlab Tutorial – Amplitude Modulation
How to generate Amplitude modulation (AM) using MATLAB? AM is a method of transmitting signals, such as sound or digital information, in which the amplitude of carrier wave is changed according to the message signal. AM is widely used in electronic communication field. The plotting of AM signal using MATLAB is very easy.
Here we are simply adding the carrier amplitude with message signal to obtain AM signal, then the instantaneous amplitude of carrier gets altered with respect to modulating signal. Thus the carrier amplitude varies according to the base band signal (message signal).

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Mourad ELGORMA

Fondateur de summarynetworks, passionné des nouvelles technologies et des métiers de Réseautique , Master en réseaux et système de télécommunications. ,j’ai affaire à Pascal, Delphi, Java, MATLAB, php …Connaissance du protocole TCP / IP, des applications Ethernet, des WLAN …Planification, installation et dépannage de problèmes de réseau informatique……Installez, configurez et dépannez les périphériques Cisco IOS. Surveillez les performances du réseau et isolez les défaillances du réseau. VLANs, protocoles de routage (RIPv2, EIGRP, OSPF.)…..Manipuler des systèmes embarqués (matériel et logiciel ex: Beaglebone Black)…Linux (Ubuntu, kali, serveur Mandriva Fedora, …). Microsoft (Windows, Windows Server 2003). ……Paquet tracer, GNS3, VMware Workstation, Virtual Box, Filezilla (client / serveur), EasyPhp, serveur Wamp,Le système de gestion WORDPRESS………Installation des caméras de surveillance ( technologie hikvision DVR………..). ,

21 réflexions sur “Amplitude Modulation – Matlab Tutorial (Amplitude modulation in Matlab with Code) 2016

  • juillet 21, 2021 à 8:19
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    Thanks a lot man! I was having a lot of trouble doing that on matlab, you helped me a lot! 😉 But, I guess the variable Ac should be multiplying in the last equation, like this: y=Ac*(1+m*sin(2*pi*fa*t)).sin(2*pi*fc*t), instead of y=Ac + (1+m . . .
    Because the signal should be oscillating between 10 and -10.

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  • juillet 21, 2021 à 8:19
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    Also, I dont get the use of the m variable. Is it used for the modulator's senstivity to show the signal is overmodulated?

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  • juillet 21, 2021 à 8:19
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    it was very helpfull
    but please just tell me that in the beginning
    here m=1
    whats representing?

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  • juillet 21, 2021 à 8:19
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    link for code: https://www.dropbox.com/s/2a8xlw1fwogu12t/first.m?dl=0

    m=1; % modulation constant Am/Ac, 1 means %100 modulating, 0.5 %50 percent etc..
    t=0 : 0.000005 : 0.003; % time for graphing, t = starting value : step size : ending value
    figure(1)

    % Modulating Signal
    Am=5;
    fa=2000;
    ym=Am*sin(2*pi*fa*t);
    subplot(3,1,1);
    plot (t,ym)
    title('Modulating signal')

    % Carrier Signal
    Ac=Am/m;
    fc=20000; % carrier frequency
    yc=Ac*sin(2*pi*fc*t);

    subplot(3,1,2)
    plot(t,yc)
    grid on;
    title('Carrier signal')

    % Modulated Signal
    y=Ac*(1+m*sin(2*pi*fa*t)).*sin(2*pi*fc*t); % in video it is + but i think it should be * , t is a matrix so you need dot for multiplying
    subplot(3,1,3)
    plot(t,y)
    title('Amplitude modulated signal')

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  • juillet 21, 2021 à 8:19
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    Here is the code to copy in case anyone need to just run the simulation with changing some values to see the results…

    clc;

    close all;

    clear all;

    m = 1;

    Am = 5; %Amp. of modulating signal

    fa = 2000; %frequency of modulating signal

    Ta = 1/fa;

    t = 0:Ta/999:6*Ta;

    ym = Am*sin(2*pi*fa*t);

    figure(1)

    subplot(3,1,1)

    plot(t,ym)

    title('Modulating Signal')

    %Carrier signal

    Ac = Am/m;

    fc = fa*10;

    Tc = 1/fc;

    yc = Ac*sin(2*pi*fc*t);

    subplot(3,1,2)

    plot(t,yc)

    grid on;

    title('Carrier Signal')

    %AM Modulation

    y = Ac + (1+m*sin(2*pi*fa*t)).*sin(2*pi*fc*t);

    subplot(3,1,3)

    plot(t,y)

    title('Amplitude Modulated Signal')

    grid on;

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  • juillet 21, 2021 à 8:19
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    For some reason, when I remove the 1+ in the modulated y calculation, it no longer is a true modulation. The spectra should show two sidebands, but it shows 1 sideband (when I remove the 1+). I will keep it as it is, but I really don't understand that part. And if I plot without the 1+ , it looks nice and modulated in time domain (though not in frequency spectra).

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