# How to save Fourier series approximated signal to a WAV file

I changed this Matlab/Octave code to approximate square wave by using combination of Fourier series and Fejér taper:

    % needed for Octave ------------------------------
% ------------------------------------------------

% Stage 1 ----------------------------------------
figure
N=20;                               % harmonics
fs = 44100;
fc = 440;
w = 2 * pi * fc;
r_start=0;
r_end=10;
r_step=1/fs;
t = r_start:r_step:r_end;           % range
w_sqr = square(w*t);          % Square wave [-1:1]

plot(t,w_sqr);
axis([r_start r_end -1.2 1.2]);
grid on;
hold on;
audiowrite("squarewave.vaw", w_sqr, fs);

% Approximation: Combined
% Fourier series-Fejér taper (Tukey window?) -----------
%i=1;
%sum=0;
%r=t;
%for t=r
%  for n=1:N
%    %sum = sum + (2*sin(n*t)+sin(pi*n-n*t)-sin(n*t+pi*n))/(2*pi*n) % Fourier series
%    %sum = sum + ((1-n/(N+1))*(-1)*sin(n*t)*(cos(n*pi)-1))/(n*pi); % Fejér taper
%    sum = sum + ((n-2*N-2)*(cos(pi*n)-1)*sin(n*w*t))/(2*pi*n*(N + 1)); % (Fourier+Fejér)/2
%  end
%   Ffej(i)= sign(sum)*(1/2) + sum;
%  i=i+1;
%  sum=0;
%end;
%Ffej=Ffej';

sum_ = sum((((1:N)-2*N-2).*(cos(pi*(1:N))-1).*sin((1:N).*w.*(0:1/fs:1)'))./(2*pi*(1:N)*(N + 1)), 2);
Ffej = 2*sum_;
Ffej = Ffej';

plot(t,Ffej);
axis([r_start r_end -1.2 1.2]);
legend('Square', 'Fourier series-Fejér taper');

audiowrite("approximated_squarewave.wav, Ffej, fs);


which results this plot: I would like to save these signals to .wav files by using Matlab/Octave audiowrite() command.

What changes are needed to be done in code to save an approximation of 440Hz square wave sound sampled at 44100 Hz? My thought is that range t must be changed to support sample rate range and frequency but, how is the situation with calculation of Ffej ... or is data of Ffej directly usable in audiowrite() command?  