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b) Compute the response of your system to the signal you defined in Question 1 using H(s) and the Fourier series coefficients of your signal.
 
b) Compute the response of your system to the signal you defined in Question 1 using H(s) and the Fourier series coefficients of your signal.
  
CT signal : <math> sin (3\pi t) </math>
+
CT signal :
 +
<math>x(t) = 6\cos(2\pi t) + 8\sin(4\pi t)\,</math>
  
<math> y(t) = e^{- s} sin (3\pi t) </math>
+
<math>x(t) = \sum^{\infty}_{k = -\infty} a_k e^{jk\pi t}\,</math>
 +
 
 +
<math>y(t) = \sum^{\infty}_{k = -\infty} a_k H(s) e^{jk\pi t}\,</math>
 +
 
 +
From Question 1:
 +
 
 +
<math>x(t) = 3e^{j2\pi t}+3e^{-j2\pi t} + 4e^{j4\pi t}-4e^{-j4\pi t}\,</math>
 +
 
 +
<math>a_1 = 3\,</math>          <math>a_{-1} = 3\,</math>
 +
 
 +
<math>a_2 = 4\,</math>          <math>a_{-2} = -4\,</math>
 +
 
 +
<math>x(t) = 3H(s)e^{j2\pi t}+3H(s)e^{-j2\pi t} + 4H(s)e^{j4\pi t}-4H(s)e^{-j4\pi t}\,</math>
 +
 
 +
<math>x(t) = 3j\omega_0e^{j2\pi t}+3j\omega_0e^{-j2\pi t} + 4j\omega_0e^{j4\pi t}-4j\omega_0e^{-j4\pi t}\,</math>
 +
 
 +
<math>\omega_0\,</math> f=2
 +
 
 +
<math>x(t) = 6je^{j2\pi t}+6je^{-j2\pi t} + 8je^{j4\pi t}-8je^{-j4\pi t}\,</math>

Latest revision as of 17:42, 26 September 2008

3. Define a CT LTI system.

System:

$ y(t)=x(t-1) $

a) Obtain the unit impulse response h(t) and the system function H(s) of your system.

$ d(t) --> System --> d(t-1)\ $

$ h(t)= d(t-1) $

$ H(s)= e^{- s} $

b) Compute the response of your system to the signal you defined in Question 1 using H(s) and the Fourier series coefficients of your signal.

CT signal : $ x(t) = 6\cos(2\pi t) + 8\sin(4\pi t)\, $

$ x(t) = \sum^{\infty}_{k = -\infty} a_k e^{jk\pi t}\, $

$ y(t) = \sum^{\infty}_{k = -\infty} a_k H(s) e^{jk\pi t}\, $

From Question 1:

$ x(t) = 3e^{j2\pi t}+3e^{-j2\pi t} + 4e^{j4\pi t}-4e^{-j4\pi t}\, $

$ a_1 = 3\, $ $ a_{-1} = 3\, $

$ a_2 = 4\, $ $ a_{-2} = -4\, $

$ x(t) = 3H(s)e^{j2\pi t}+3H(s)e^{-j2\pi t} + 4H(s)e^{j4\pi t}-4H(s)e^{-j4\pi t}\, $

$ x(t) = 3j\omega_0e^{j2\pi t}+3j\omega_0e^{-j2\pi t} + 4j\omega_0e^{j4\pi t}-4j\omega_0e^{-j4\pi t}\, $

$ \omega_0\, $ f=2

$ x(t) = 6je^{j2\pi t}+6je^{-j2\pi t} + 8je^{j4\pi t}-8je^{-j4\pi t}\, $

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