(New page: == Basics of Linearity == Image:ECE301HW3.JPG We are given the following information: For input <math>x(t) = e</math> <sup>(2jt)</sup> the output <math> y(t) = te</math><sup>(-2jt)<...)
 
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We are given the following information:
 
We are given the following information:
  
For input <math>x(t) = e</math> <sup>(2jt)</sup> the output <math> y(t) = te</math><sup>(-2jt)</sup>.
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* For input <math>x(t) = e</math> <sup>(2jt)</sup> the output <math> y(t) = te</math><sup>(-2jt)</sup>.
  
For input <math>x(t) = e</math> <sup>(-2jt)</sup> the output <math> y(t) = te</math><sup>(2jt)</sup>.
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* For input <math>x(t) = e</math> <sup>(-2jt)</sup> the output <math> y(t) = te</math><sup>(2jt)</sup>.
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* The system is Linear.
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We can break down the input <math> \,\ x(t) = cos(2t) </math> into <math> \,\ x(t) = \frac{1}{2} * (e</math><sup>(j2t)</sup> <math> \,\ + e</math><sup>(-j2t)</sup><math> \,\ )</math>.
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Now we can use the property of linearity to determine the output.
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We already know the outputs of the two individual parts of <math> cos(2t) </math>.  All we have to do is add them together to find the output <math> z(t) </math>.
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<math> \,\ \frac{1}{2} * (e</math><sup>(j2t)</sup> <math> \,\ + e</math><sup>(-j2t)</sup><math> \,\ )  \rArr </math> SYSTEM <math> \,\ \rArr \frac{1}{2} * te</math><sup>(-2jt)</sup> + <math> \,\ \frac{1}{2} * te</math><sup>(2jt)</sup>
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<math> \,\ \frac{1}{2} * te</math><sup>(-2jt)</sup> + <math> \,\ \frac{1}{2} * te</math><sup>(2jt)</sup> <math> = t * \frac{1}{2} * (e</math><sup>(j2t)</sup> <math> \,\ + e</math><sup>(-j2t)</sup><math> \,\ ) </math>
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<math> t * \frac{1}{2} * (e</math><sup>(j2t)</sup> <math> \,\ + e</math><sup>(-j2t)</sup><math> \,\ ) = t*cos(2t) </math>
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Therefore, the input signal <math> \,\ x(t) = cos(2t) </math> yields an output signal of <math> \,\ z(t) = tcos(2t) </math>

Latest revision as of 12:29, 16 September 2008

Basics of Linearity

ECE301HW3 ECE301Fall2008mboutin.JPG

We are given the following information:

  • For input $ x(t) = e $ (2jt) the output $ y(t) = te $(-2jt).
  • For input $ x(t) = e $ (-2jt) the output $ y(t) = te $(2jt).
  • The system is Linear.


We can break down the input $ \,\ x(t) = cos(2t) $ into $ \,\ x(t) = \frac{1}{2} * (e $(j2t) $ \,\ + e $(-j2t)$ \,\ ) $.

Now we can use the property of linearity to determine the output.


We already know the outputs of the two individual parts of $ cos(2t) $. All we have to do is add them together to find the output $ z(t) $.

$ \,\ \frac{1}{2} * (e $(j2t) $ \,\ + e $(-j2t)$ \,\ ) \rArr $ SYSTEM $ \,\ \rArr \frac{1}{2} * te $(-2jt) + $ \,\ \frac{1}{2} * te $(2jt)

$ \,\ \frac{1}{2} * te $(-2jt) + $ \,\ \frac{1}{2} * te $(2jt) $ = t * \frac{1}{2} * (e $(j2t) $ \,\ + e $(-j2t)$ \,\ ) $

$ t * \frac{1}{2} * (e $(j2t) $ \,\ + e $(-j2t)$ \,\ ) = t*cos(2t) $


Therefore, the input signal $ \,\ x(t) = cos(2t) $ yields an output signal of $ \,\ z(t) = tcos(2t) $

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