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[[Homework 4_ECE301Fall2008mboutin|<< Back to Homework 4]]
 
[[Homework 4_ECE301Fall2008mboutin|<< Back to Homework 4]]
  
Homework 4 Ben Horst:  [[HW4.1 Ben Horst _ECE301Fall2008mboutin| 4.1]] :: [[HW4.2 Ben Horst _ECE301Fall2008mboutin| 4.2]] ::  [[HW4.3 Ben Horst _ECE301Fall2008mboutin| 4.3]] :: [[HW4.4 Ben Horst _ECE301Fall2008mboutin| 4.4]] :: [[HW4.5 Ben Horst _ECE301Fall2008mboutin| 4.5]]
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Homework 4 Ben Horst:  [[HW4.1 Ben Horst _ECE301Fall2008mboutin| 4.1]] :: [[HW4.3 Ben Horst _ECE301Fall2008mboutin| 4.3]] ::  [[HW4.5 Ben Horst _ECE301Fall2008mboutin| 4.5]]
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----
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==System==
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y(t) = 3x(t) which is proven as an LTI system ([[HW2-C_Ben_Horst _ECE301Fall2008mboutin| shown here]])
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==Impulse Response==
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y(<math>\delta(t)</math>) = 3(<math>\delta(t)</math>)
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=>impulse response = <math>3\delta(t)</math>
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 +
 
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==System Function==
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Find H(s):
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H(<math>j\omega</math>) = <math> \int_{-\infty}^{\infty}h(\tau)e^{-j\omega\tau}d\tau</math>, where <math>j\omega</math> is <em>s</em>.
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 +
 
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H(s) = <math> \int_{-\infty}^{\infty}h(\tau)e^{-s\tau}d\tau</math>
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H(s) = <math> \int_{-\infty}^{\infty}3\delta(\tau)e^{-s\tau}d\tau</math>
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By the Sifting property, this is:
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H(s) = <math>3e^0</math>
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thus,
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H(s) = <math>3</math>
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==Example Response==
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===Input===
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From previous part of homework:
 +
 
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<math>x(t) = 2\sin(6t) + 4\cos(3t)</math>
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===Info===
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From the [[HW4.1 Ben Horst _ECE301Fall2008mboutin| previously computed]] math, we can determine all the coefficients:
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<math> \ \ a_{-2} = 1; \ \ a_{-1} = 2; \ \ a_{0} = 0; \ \  a_1 = 2;\ \ a_{2} = -1 </math>
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The fundamental period of the function is found from: <math>e^{j\omega_0}</math> where he period T = <math>{2\pi \over \omega_o}</math>
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Thus, the fundamental period = <math> {2\pi \over 3} </math>
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===Response===
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Given that y(t) = <math>\sum_{k=-\infty}^{\infty} a_kH(j\omega_0 k) e^{j\omega_0 k}</math> from pg228 in Signals and Systems (Oppenheim & Willsky)
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 +
 
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Thus:
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y(t) = 1(3)<math>e^{-2jt}</math> + 2(3)<math>e^{-1jt}</math> + 0(3)<math>e^{0jt}</math> + 2(3)<math>e^{1jt}</math> - 1(3)<math>e^{2jt}</math>
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y(t) = 3<math>e^{-2jt}</math> + 6<math>e^{-jt}</math> + 6<math>e^{jt}</math> - 3<math>e^{2jt}</math>

Latest revision as of 17:34, 25 September 2008

<< Back to Homework 4

Homework 4 Ben Horst: 4.1 :: 4.3 :: 4.5


System

y(t) = 3x(t) which is proven as an LTI system ( shown here)

Impulse Response

y($ \delta(t) $) = 3($ \delta(t) $)

=>impulse response = $ 3\delta(t) $


System Function

Find H(s):

H($ j\omega $) = $ \int_{-\infty}^{\infty}h(\tau)e^{-j\omega\tau}d\tau $, where $ j\omega $ is s.


H(s) = $ \int_{-\infty}^{\infty}h(\tau)e^{-s\tau}d\tau $


H(s) = $ \int_{-\infty}^{\infty}3\delta(\tau)e^{-s\tau}d\tau $


By the Sifting property, this is:

H(s) = $ 3e^0 $

thus,

H(s) = $ 3 $

Example Response

Input

From previous part of homework:

$ x(t) = 2\sin(6t) + 4\cos(3t) $

Info

From the previously computed math, we can determine all the coefficients: $ \ \ a_{-2} = 1; \ \ a_{-1} = 2; \ \ a_{0} = 0; \ \ a_1 = 2;\ \ a_{2} = -1 $

The fundamental period of the function is found from: $ e^{j\omega_0} $ where he period T = $ {2\pi \over \omega_o} $

Thus, the fundamental period = $ {2\pi \over 3} $


Response

Given that y(t) = $ \sum_{k=-\infty}^{\infty} a_kH(j\omega_0 k) e^{j\omega_0 k} $ from pg228 in Signals and Systems (Oppenheim & Willsky)


Thus:

y(t) = 1(3)$ e^{-2jt} $ + 2(3)$ e^{-1jt} $ + 0(3)$ e^{0jt} $ + 2(3)$ e^{1jt} $ - 1(3)$ e^{2jt} $


y(t) = 3$ e^{-2jt} $ + 6$ e^{-jt} $ + 6$ e^{jt} $ - 3$ e^{2jt} $

Alumni Liaison

has a message for current ECE438 students.

Sean Hu, ECE PhD 2009