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Fourier series / calculate power over resistor

  1. Jan 25, 2014 #1
    1. The problem statement, all variables and given/known data

    V(t) = 4 for 0<t< 1 and 0 for 1<t<3 and repeats itself for all t (negative and positive)

    Find the first 5 harmonics of the fourier series in cosine form and find the power if this is the voltage over 100 ohm resistor


    3. The attempt at a solution


    power = d_dc ^2 / R + .5sum from n=1 to 5 of |v_n|^2 /R = 0.1385 w

    This does not seem correct. I am not sure where I went wrong.
     
    Last edited: Jan 25, 2014
  2. jcsd
  3. Jan 25, 2014 #2

    rude man

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    Where does the sinc come from? Is this some kind of discrete system?
     
  4. Jan 25, 2014 #3
    It is a square wave.
     
    Last edited: Jan 25, 2014
  5. Jan 25, 2014 #4

    rude man

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    Why don't you simmply use the integrals for the a_n and b_n coefficients? Then get the series in the form

    V(t) = c0 + 2 ∑n=1 to 5 of cn cos(nω1t + øn)?

    And what exactly is x_n?
     
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