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Homework Help: Unit time step signal

  1. Aug 2, 2011 #1
    1. The problem statement, all variables and given/known data

    Solvinf the unit time step equation mathematically.

    2. Relevant equations

    x(t) = u(t+1) - 2u(t) + u(t-1)

    3. The attempt at a solution

    How can i solve this signal mathemtically :( and using plotted signals , i couldn't understand,

    here is my approach and i'm not sure it is correct,

    i simply wrote the coordiantes of each signal,

    u(t+1) = (-1,1)

    -2ut = (0,-2)

    u(t-1) = (1,1)

    and then added them which give answer = '0' :(

    is this the way of solving the signals ?
    please help
  2. jcsd
  3. Aug 2, 2011 #2


    User Avatar

    Staff: Mentor

    The result should be a signal that varies with time. You've identified the important times where "interesting things" take place -- the various unit step functions change value at these times.

    If you were to draw several time axes stacked one over the other and plot the individual step functions, one per time axis, you might be able to see how the functions will sum up.
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