plotting Sum function , with floor term and rectangular pulse

Hey,

Is there a way to plot this function in Matlab?

y(t) =

while is the function : , and u is the Heaviside function.

Answer 1

[Ameer Hamza]

try this

syms t n

chi = heaviside(t-n) - heaviside(t-2-n);
term = (-1)^n*floor((n+2)/2).*chi;
y = symsum(term, n, 0, inf);

t_vec = linspace(0, 10, 100);
y_vec = vpa(subs(y, t, t_vec));
plot(t_vec, y_vec, '-o')

A faster alternative:

chi = @(t, n) heaviside(t-n) - heaviside(t-2-n);
term = @(t, n) (-1).^n.*floor((n+2)/2).*chi(t,n);
y = @(t) sum(term(t, 0:ceil(t+1)));

t_vec = linspace(0, 10, 100);
y_vec = zeros(size(t_vec));
for i=1:numel(t_vec)
     y_vec(i) = y(t_vec(i));
end
plot(t_vec, y_vec, '-o')

[Ameer Hamza]

The second code is faster and it takes advantage of the fact that for n > t, the term become zero, so no need to sum those terms.

[semicolon]

Thank you :)

[Ameer Hamza]

Glad to be of help.