a=(rand(1,5)>0.5)+0.3;
x=0:0.02:2;
y=[];
for i=1:length(a);
    y=[y,a(i)*sin(pi*x)];
end

plot(y)
grid on
xlabel('t');
ylabel('y');
title('amplitude modulation ');
Ts=1;
w=-120:1:120;
Wh=50;
for i=1:length(w)
    if(abs(w(i))<=100)
        h(i)=Ts*(1+cos(w(i)*pi/(2*Wh)))/2;
    else 
        h(i)=0;
    end
end
figure;
subplot(1,2,1)
plot(w,h)
xlabel('f');
ylabel('|G(f)|');
fc=300;
w1=-(fc+120):1:fc+120;
for i=1:length(w1)
    if(abs(w1(i)+fc)<=100)
        h1(i)=Ts*(1+cos((w1(i)+fc)*pi/(2*Wh)))/2;
    else if abs(w1(i)-fc)<=100
         h1(i)=Ts*(1+cos((w1(i)-fc)*pi/(2*Wh)))/2;    
    else 
        h1(i)=0;
    end
end
subplot(1,2,2)
plot(w1,h1)