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Homework Help: Discrete time signal to continuous time signal

  1. Sep 28, 2008 #1
    1. The problem statement, all variables and given/known data
    Suppose that a discrete-time signal x[n] is given by the formula

    x[n] = 10cos(0.2*PI*n - PI/7)

    and that it was obtained by sampling a continuous signal at a sampling rate of fs=1000 samples/second.

    Determine two different continuous-time signals x1(t) and x2(t) whose samples are equal to x[n]; ie. find x1(t) and x2(t) such that x[n] = x1(nTs) = x2(nTs0 if Ts = 0.001. Both of these signals should have a frequency less than 1000Hz. Give a formula for each signal.

    3. The attempt at a solution

    Since x[n] = 10 * cos ( 0.2 * PI * n - PI / 7)
    The same signal would be represented by

    x[n] = 10 * cos(2.2 * PI * n - PI/7)

    Is this assumption correct?

    Now I would need to convert these two x[n] equations to time-domain x(t), and I am not sure how I would go about doing this part.
  2. jcsd
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