fourier series

Discussion in 'Homework Help' started by hamza324, Oct 18, 2011.

  1. hamza324

    Thread Starter Member

    Jul 10, 2011
    I am trying to solve fourier series problems. i have few confusions about that..

    1) x(t) =\sum c_x(k)e ^{jkwt}

    where as c_x(k) = \int_T x(t) e^{-jwt} dt

    My question is that when which equation do we use to plot the graph.
    and how do we take the values for the graph. Is it BODE PLOTS or is it simply plugging in the values.

    suppose i havethis expression
    c_x(k)= A/2 \frac {cos(k\prod-1)}{k\prod}^2

    or\ i\ have\ c_x(k)= A/2 \frac {sinc(k\prod-1)}{k\prod}^2

    then how can i graph this equation for c_1\ ,\ c_2\ ,\ ......
  2. Georacer


    Nov 25, 2009
    Are these equations for c_x(k) correct? The multiplication symbol has no argument in either of them. It refers to the product of what?
  3. hamza324

    Thread Starter Member

    Jul 10, 2011
    The question i have is f(t)= A\ cos200\pi t
    and this is the expression for fourier series x(t) = \sum^{+\infty}_{k=-\infty}c_ke^{j2wkt}

    i got the following solution for fourier coefficients

    now\ for\ c_k\ =-\frac{1}{4}\frac{Sin(\pi +k)(0.5)}{(\pi+k)}-\frac{1}{4}\frac{Sin(\pi - k)0.5}{\pi-k}-\frac{1}{4}\frac{Sin(\pi+k)1.5}{\pi+k}-\frac{1}{4}\frac{Sin(\pi-k)1.5}{\pi-k}

    Now my prof asks me to sketch the fourier series coefficients i.e. c_k\ for\ k=\ 1,2,3,....

    I wanna know how to sketch the result i got