Issue with Fourier Series Stair Step Function

I am supposed to be seeing a stair step function, but I get a striaght line instread. I am seeing this warning "Warning: Imaginary parts of complex X and/or Y arguments ignored ". What could be causing this?

Code:

n_count = 400;

t_count = [0:0.01:24];

y_count = Fourier_Function(n_count, t_count);

figure;

plot(t_count, y_count);

title("Stair Step Function for Problem 4");

xlabel("Time (s)");

ylabel("Signal Magnitude (v)");

function [ff] = Fourier_Function(n, t)

ff = 1; %Ao term acting as 1 and allowing sum functionality

for i = 1:1:n %Acting as our n vairable

An = (-1/(-2j*pi*i)).*((exp((-2j*pi*i)/3) - 2.*(exp((-4j*pi*i)/3)))).*exp((-j*pi)/2);

An_Conj = conj(An);

ff = ff + An.*exp((2j*pi*i*t)/3).* An_Conj .*exp((-2j*pi*i*t)/3);

end

end

Answer 1

[VBBV]

n_count = 400;  
t_count = [0:1:24];
y_count = Fourier_Function(n_count, t_count);
figure;
plot(t_count, abs(y_count),'-.');
title("Stair Step Function for Problem 4");
xlabel("Time (s)");
ylabel("Signal Magnitude (v)");

function [Ff] = Fourier_Function(n, t)
    ff = 1; %Ao term acting as 1 and allowing sum functionality
    for k = 1:length(t)
        for i = 1:1:n %Acting as our n vairable 
            An = (-1/(-2j*pi*i)).*((exp((-2j*pi*i)/3) - 2.*(exp((-4j*pi*i)/3)))).*exp((-j*pi)/2);
            An_Conj = conj(An);
            ff = real(ff) + An.*exp((2j*pi*i*t(k))/3)+An_Conj .*exp((-2j*pi*i*t(k))/3);
        end
    Ff(k,:) = ff;
    end
    Ff;
end 

Do you mean this ? functions needs to be modified

[OvercookedRamen]

I got it to work, sort of. This is what I meant as a stair step function. Except it should be even.

n_count = 400;

t_count = [0:0.01:24];

y_count = Fourier_Function(n_count, t_count);

figure;

plot(t_count, y_count);

title("Stair Step Function for Problem 4");

xlabel("Time (s)");

ylabel("Signal Magnitude (v)");

function [ff] = Fourier_Function(n, t)

ff = 1; %Ao term acting as 1 and allowing sum functionality

for i = 1:1:n %Acting as our n vairable

%An = (1/(2j*pi*i)) * (exp((-2j*pi*i)/3) - 2*exp((-4j*pi*i)/3) + 1) * exp((-1j*pi)/2);

An = (-1/(2j*pi*i)) * ((exp((-2j*pi*i)/3)-1)) - ((-1/(1j*pi*i))) * (exp((-4j*pi*i)/3) - exp((-2j*pi*i)/3));

An_Conj = conj(An);

ff = ff + An * exp((2j*pi*i*t)/3) + An_Conj *exp((-2j*pi*i*t)/3);

end

end