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Homework Help: Convolution with unit step

  1. Sep 28, 2014 #1
    1. The problem statement, all variables and given/known data
    Find convolution of x[n] (graph in attachment) and h[n] where h[n] = u[n]
    2. Relevant equations

    3. The attempt at a solution
    - flipped the h[n] to have h[-n]
    - moved to the left once (h[-1-n]) to align
    - multiplied h and x and it gives me all zeros

    Is this correct or I'm missing something?
  2. jcsd
  3. Sep 29, 2014 #2

    rude man

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    I don't know about your graphical algorithm but if you use the definition

    y[n] = x[n]*h[n] = ∑ (k = -∞ to +∞) x[k] h[n-k]

    then I get a non-zero sequence of numbers:

    a+0.5, b+0.5, c+0.5, c+0.5, d+0.5, d+0.5, d+ 0.5, ...

    wher a, b , c, and d are positive integers for you to find.
  4. Sep 29, 2014 #3

    rude man

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  5. Oct 1, 2014 #4
    Just think x(n) as sum of shifted and scaled impulses . Since you know the convolution of a signal h(n) with shifted impulse will be shifted h(n) and then you add them .
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