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## Amplitude Modulation (AM) in time and frequency domain

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Amplitude Modulation (AM) in time and frequency domain

Updated 10 Apr 2016

Amplitude Modulation (AM) in time and frequency (FFT) domain with fs=220500 Hz, fc=2000 Hz and fm=300 Hz. FIND MORE HERE: http://www.behindthesciences.com/signal-processing/amplitudemodulationammatlabtutorial

### Cite As

Behind The Sciences (2021). Amplitude Modulation (AM) in time and frequency domain (https://www.mathworks.com/matlabcentral/fileexchange/56465-amplitude-modulation-am-in-time-and-frequency-domain), MATLAB Central File Exchange. Retrieved .

### Comments and Ratings (3)

A=8;
A1=8;
f=5;
f1=8*f;
t=linspace(0,1,1000);
m=A/A1;
wm=2*pi*f*t;
wc=2*pi*f1*t;
Am=A*sin(wm);

%%"Message Signal"%%
subplot(3,2,1)
plot(t,Am,'b');
ylabel('<---Amplitude--->','Fontsize',11);
xlabel('<---Timeperiod--->','Fontsize',11);
title('***Message signal***','Fontsize',15);

%%" Carrier Signal"%%
Ac=A1*sin(wc);
subplot(3,2,2)
plot(t,Ac,'r');
ylabel('<---Amplitude--->','Fontsize',11);
xlabel('<---Timeperiod--->','Fontsize',11);
title('***Carrier Signal***','Fontsize',15);

%%.."Critical (100%) Modulation"..%%
A=5;
A1=5;
m=A/A1;
Mc=A1*[1+m*sin(2*pi*f*t)].*[sin(2*pi*f1*t)];
subplot(3,2,3)
x=hilbert(Mc);
env=abs(x);
plot_para={'color',[1 .8 .5],'Linewidth',.2};
plot(t,Mc,'g')
hold on
plot(t,[-1;1]*env,plot_para{:});
hold off;
ylabel('<---Amplitude--->','Fontsize',11);
xlabel('<---Timeperiod--->','Fontsize',11);
title('***Critical Modulation (100%) signal***','Fontsize',15)

%%.."Under (50%) Modulation "..%%
A=3.5;
A1=5;
m=A/A1;
Mu=A1*[1+m*sin(2*pi*f*t)].*[sin(2*pi*f1*t)];
subplot(3,2,4)
z=hilbert(Mu);
env=abs(z);
plot_para={'color',[1 0.5 0],'Linewidth',.2};
plot(t,Mu,'m')
hold on
plot(t,[-1;1]*env,plot_para{:});
hold off;
ylabel('<---Amplitude--->','Fontsize',11);
xlabel('<---Timeperiod--->','Fontsize',11);
title('***Under Modulation (50%) Signal***','Fontsize',15)

%%.."Over (150%) Modulation"..%%
A=20;
A1=10;
m=A/A1;
Mo=A1*[1+m*sin(2*pi*f*t)].*[sin(2*pi*f1*t)];
subplot(3,2,5)
y=hilbert(Mo);
env=abs(y);
plot_para={'color',[1 1 0],'Linewidth',.2};
plot(t,Mo,'c')
hold on
plot(t,[-1;1]*env,plot_para{:});
hold off;
ylabel('<---Amplitude--->','Fontsize',11);
xlabel('<---Timeperiod--->','Fontsize',11);
title('***Over Modulation(150%) Signal***','Fontsize',15)

%%.."DSB-SC"..%%
dsb=Am.*Ac;
subplot(3,2,6)
y=hilbert(dsb);
env=abs(y);
plot_para={'color',[0 1 1],'Linewidth',.2};
plot(t,dsb,'b')
hold on
plot(t,[-1;1]*env,plot_para{:});
hold off;
ylabel('<---Amplitude--->','Fontsize',11);
xlabel('<---Timeperiod--->','Fontsize',11);
title('***DSB-SC Signal***','Fontsize',15);
ylim([-100, 100]);

Nazar Bulavko

Awesome!
Thx for script))

amine milano

##### MATLAB Release Compatibility
Created with R2015a
Compatible with any release
##### Platform Compatibility
Windows macOS Linux

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