b = [1]; a = [1, -0.9]; n = [-5:50];

h = impz(b,a,n);

set(gcf,'Color','white');

%subplot(2,1,1);

stem(n,h); title('Impulse Response');

xlabel('n'); ylabel('h(n)'); grid on;

x = stepseq(0, -5, 50) - stepseq(10, -5, 50)

y = filter(b, a, x);

figure; set(gcf,'Color','white');

%subplot(2, 1,2);

stem(n,x); title('Step Sequence');

xlabel('n'); ylabel('x(n)'); grid on;

figure; set(gcf,'Color','white');

%subplot(2, 1,2);

stem(n,y); title('Output Sequence');

xlabel('n'); ylabel('y(n)'); axis([-5,50,-0.5,8]);

grid on;