Randall Low

 

 

This is a plot of the line spectra for the square wave function.

Graph of the square wave function (Fourier series approx.)

 

The Trigonometric Fourier Series Coefficients of x(t) are:

-----------------------------------------------------------------------

       n             c(n)            

 -20.0000            -0.0000 + 0.0000i

 -19.0000            -0.0335 - 0.0000i

 -18.0000             0.0000 - 0.0000i

 -17.0000             0.0374 + 0.0000i

 -16.0000            -0.0000 - 0.0000i

 -15.0000            -0.0424 - 0.0000i

 -14.0000             0.0000 + 0.0000i

 -13.0000             0.0490 + 0.0000i

 -12.0000            -0.0000 + 0.0000i

 -11.0000            -0.0579 - 0.0000i

 -10.0000             0.0000 - 0.0000i

  -9.0000             0.0707 + 0.0000i

  -8.0000            -0.0000 + 0.0000i

  -7.0000            -0.0909 - 0.0000i

  -6.0000             0.0000 + 0.0000i

  -5.0000             0.1273 + 0.0000i

  -4.0000            -0.0000 + 0.0000i

  -3.0000            -0.2122 - 0.0000i

  -2.0000             0.0000 - 0.0000i

  -1.0000             0.6366 + 0.0000i

        0            -0.0000         

   1.0000             0.6366 - 0.0000i

   2.0000             0.0000 + 0.0000i

   3.0000            -0.2122 + 0.0000i

   4.0000            -0.0000 - 0.0000i

   5.0000             0.1273 - 0.0000i

   6.0000             0.0000 - 0.0000i

   7.0000            -0.0909 + 0.0000i

   8.0000            -0.0000 - 0.0000i

   9.0000             0.0707 - 0.0000i

  10.0000             0.0000 + 0.0000i

  11.0000            -0.0579 + 0.0000i

  12.0000            -0.0000 - 0.0000i

  13.0000             0.0490 - 0.0000i

  14.0000             0.0000 - 0.0000i

  15.0000            -0.0424 + 0.0000i

  16.0000            -0.0000 + 0.0000i

  17.0000             0.0374 - 0.0000i

  18.0000             0.0000 + 0.0000i

  19.0000            -0.0335 + 0.0000i

  20.0000            -0.0000 - 0.0000

 

 

 

 

 

 

 

Now for the less accurate Fourier Series graph and corresponding trigonometric coefficients:

 

 

a0=

 -5.2947e-010

 

    n             a(n)        b(n)

    1.0000    1.2732   -0.0000

    2.0000    0.0000    0.0000

    3.0000   -0.4244    0.0000

    4.0000   -0.0000   -0.0000

    5.0000    0.2546   -0.0000

 

These are coefficients for triangle function.

The Trigonometric Fourier Series Coefficients of x(t) are:

-----------------------------------------------------------------------

       n             c(n)            

 -20.0000             0.0000 + 0.0000i

 -19.0000             0.0000 + 0.0011i

 -18.0000             0.0000 + 0.0000i

 -17.0000                  0 - 0.0014i

 -16.0000             0.0000 + 0.0000i

 -15.0000             0.0000 + 0.0018i

 -14.0000             0.0000 + 0.0000i

 -13.0000             0.0000 - 0.0024i

 -12.0000             0.0000 - 0.0000i

 -11.0000            -0.0000 + 0.0033i

 -10.0000                  0 - 0.0000i

  -9.0000            -0.0000 - 0.0050i

  -8.0000             0.0000 - 0.0000i

  -7.0000            -0.0000 + 0.0083i

  -6.0000                  0 + 0.0000i

  -5.0000            -0.0000 - 0.0162i

  -4.0000             0.0000 + 0.0000i

  -3.0000            -0.0000 + 0.0450i

  -2.0000             0.0000 - 0.0000i

  -1.0000                  0 - 0.4053i

        0                  0         

   1.0000                  0 + 0.4053i

   2.0000             0.0000 + 0.0000i

   3.0000            -0.0000 - 0.0450i

   4.0000             0.0000 - 0.0000i

   5.0000            -0.0000 + 0.0162i

   6.0000                  0 - 0.0000i

   7.0000            -0.0000 - 0.0083i

   8.0000             0.0000 + 0.0000i

   9.0000            -0.0000 + 0.0050i

  10.0000                  0 + 0.0000i

  11.0000            -0.0000 - 0.0033i

  12.0000             0.0000 + 0.0000i

  13.0000             0.0000 + 0.0024i

  14.0000             0.0000 - 0.0000i

  15.0000             0.0000 - 0.0018i

  16.0000             0.0000 - 0.0000i

  17.0000                  0 + 0.0014i

  18.0000             0.0000 - 0.0000i

  19.0000             0.0000 - 0.0011i

  20.0000             0.0000 - 0.0000i

 

Below is a graph of the line amplitude spectrum for the triangle function.

 

This is the graph of the triangle function’s Fourier Series approximations.

Here are the trigonometric approximations of Fourier Series approximations corresponding to the graph of x(t), the triangle function above.

a0=

     0

 

   n             a(n)        b(n)

    1.0000         0    0.8106

    2.0000    0.0000   -0.0000

    3.0000         0   -0.0901

    4.0000         0    0.0000

    5.0000   -0.0000    0.0324