N=input('Please give an integer >30 :');
n=[0:N-1];
alfa=0.95*exp(1j*pi/3);
h=alfa.^n;
stem(n,abs(h))
xlabel('n \rightarrow');
ylabel('Magnitude \rightarrow');
legend('Envelope')
title('Complex Exponential');

subplot(3,1,1);
stem(n,real(h));
ylabel('RE(h)');
x=[zeros(1,20) ones(1,10) zeros(1,N-30)];

subplot(3,1,2);
stem(n,x);
ylabel('x[n]')

y=conv(real(h),x);
subplot(3,1,3);
stem(n,y(1:N),'mp');
ylabel('y[n]')