Hi Dimitrios,
Assuming a general Sideband-Suppressed modulation case, we can take a case of modulating a simple sine wave message signal of frequency fm (say 0.2*fc < fc) and an amplitude of 5, along with a sampling rate fs (> 2*fc : Nyquist Condition), we can plot each of the message, modulated and demodulated signals using the following snippet:
% Carrier Frequency
fc = 522;
% Sampling Frequency (> 2*fc)
fs = 100*fc;
% Message Signal Frequency
fm = 0.2*fc;
% Time Frame : 0 to 0.01 (s)
t = (0:(1/fs):0.02);
% Original Message Signal m(t)
m = 5*sin(2*pi*fm*t);
% Amplitude Modulated Signal
y_am = ammod(m, fc, fs);
% Amplitude Demodulated Signal
y_m = amdemod(y_am, fc, fs);
% Plotting each signal
plot(t, m)
hold on
plot(t, y_am)
plot(t, y_m, "o-")
hold off
legend(["Original Signal" "Amplitude Modulated Signal" "Demodulated Signal"]);
