curves are incorrect. Fourier Series.

I WANT TO PLOT A FOURIER SERIES FOR DIFFERENT HARMONICS AS PER THE Y~t RELATION DEFINED BELOW. (TIME PERIOD=2 SECS. Y=1 for first 0.8 secs and Y=-1 for next 1.2 secs).

THE CURVES ARE NOT CORRECT,I GUESS.

t=[-1,0,0,0.8,0.8,1]';
Y=[-1,-1,1,1,-1,-1];
f=0;
for n=1:20:40
    line(t,Y,'color','r','linewidth',2)
    grid on;
  hold on;
    A=0.5*trapz(t,Y);
    P=Y.*(cos(n*pi*t))';
    Q=Y.*(sin(n*pi*t))';
    Ax=trapz(t,P);
    Bx=trapz(t,Q);
    f=f+(Ax*cos(pi*n*t)+Bx*sin(pi*n*t));
    final=A+f;
    plot(t,final,'linewidth',2)
end

[Image Analyst]

I fixed your formatting. Please read this: http://www.mathworks.com/matlabcentral/answers/13205-tutorial-how-to-format-your-question-with-markup

and these:

http://www.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer

http://blogs.mathworks.com/videos/2012/07/03/debugging-in-matlab/

"THE CURVES ARE NOT CORRECT,I GUESS." is not very descriptive. The code (after I fixed the formatting) did run and produce a plot. What would correct curves look like? Come on, make it easy for us to help you, not hard. Post a plot of what the curve should look like. If you can't use the debugger to figure out what's going wrong in this alphabet soup of code, then put in some comments, give the variables descriptive names to help up, and come back with any questions about your lastest, improved code.

Answer 1

[Rick Rosson]

I would recommend using the fft function.