signal

clear
clc
u = 0.6;
fc = 300e3;
fs = 10e3;
T = 1/fs;
t=[0:1/(180*fc):T-eps];
m = cos (2*pi*fs*t);
c = cos (2*pi*fc*t);
s_dsb = m.*c;
s_am = (1+u*m).*c;
figure (1);
subplot (2,1,1);
title('Modulated plot of a cos signal');
xlabel('time [s]');
ylabel('Amplitude [V]');
plot (t, s_dsb, t, m);
f_s_am = fft (s_dsb);
subplot (2,1,2);
plot (t, f_s_am, 'linewidth', 2);
figure (2);
xlabel ('time [s]');
ylabel ('Amplitude [V]');
plot (t, s_am,t, m);