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Homework Help: Impulse Response Function Problem

  1. Apr 24, 2013 #1

    I attempted by inputting u(τ-t)u(t-τ) into the second part of the integral. Since I want to change the second part of the integral to go from [+∞, -∞]. And as for first part of the integral I added a u(t-τ) term after the x(τ) to change the integral from [t,-∞] into [+∞, -∞]. I am not sure if I did them right. And after factoring out the common term x(τ)u(t-τ) (I assume this is my input) from the two integrals I get that my IRF h(t,τ) = 1 + e^(t-τ) * u(τ-t). I am not sure about the answer and I did not know how to solve for the Unit Step Response of this system. Please Help. Thank you.
  2. jcsd
  3. Apr 25, 2013 #2
    Hello abcz4113,

    At first thought, I would separate the cases where [itex]t<0[/itex], [itex]t=0[/itex] and [itex]t>0[/itex], assuming your impulse or unit step happens at [itex]t=0[/itex], and use the knowledge of [itex]h(t)[/itex] and [itex]g(t)[/itex].

    I will have a closer look at this in a moment.
  4. Apr 25, 2013 #3

    rude man

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    My first observation is that this system seems to be non-causal. Compare the first integral to the convolution integral relating input to output, then ask yourself what the second integral is doing there ...
  5. Apr 25, 2013 #4
    Thank you for your hints. I know how to do it now.
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