AM modulation

clc;
Ac=2;
fc=.9;

Am=.5;
fm=.05;
Fs=100;

ka=1;

t=[0:0.1:50];
ct=Ac*cos(2*pi*fc*t);
mt=Am*cos(2*pi*fm*t);
DSBAMt=ct.*(1+ka*mt);

subplot(2,2,1);
plot(mt);
ylabel('message signal');
grid on;

subplot(2,2,2);
plot(ct);
ylabel('carrier');
grid on;

subplot(2,2,3);
plot(DSBAMt);
ylabel('DSBAM signal');
grid on;