signals and systems

Discussion in 'Homework Help' started by saradahm, Aug 10, 2008.

  1. saradahm

    Thread Starter New Member

    Aug 10, 2008
    1
    0
    Huy guys....have the following questions from signals and systems....

    Determine whether the following signals is periodic...If it is periodic determine its fundamental period....

    a) 2cos(9t+pi/6)
    b) x(t) = sin^2(t-pi/6)
    c)x[n] = cos((pi*n^2)/8)
    d)x[n] = 5sin((3pi/8)*n) + 3cos((pi/6)*n)

    I have attached the file with the questions.....
     
  2. roddefig

    Active Member

    Apr 29, 2008
    149
    0
    See [post]78406[/post].
     
  3. silvrstring

    Active Member

    Mar 27, 2008
    159
    0
    That's nice. Where's your work?
     
  4. roddefig

    Active Member

    Apr 29, 2008
    149
    0
    What do you mean?

    Edit: Ack, sorry, I thought silvrstring was the OP. Disregard my question.
     
    Last edited: Aug 11, 2008
  5. blazedaces

    Active Member

    Jul 24, 2008
    130
    0
    roddefig gave you your answer. We're not here to do your homework for you.

    But just to add a comment, it might help for part d to know that the sum of two periodic signals is periodic if the ratio of their individual fundamental frequencies is a rational number.

    Think about the concept. Periodic. Plot each of those out using matlab or a calculator and look at the signals. Periodic means it repeats. Now think about that and think about the info roddefig gave you. You can easily connect the dots.

    Good luck,
    -blazed
     
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