Line 26: Line 26:
 
I'm not sure if I'm right though because when I checked it in matlab the answer I got was  
 
I'm not sure if I'm right though because when I checked it in matlab the answer I got was  
  
<pre> 4*(68+w^2)/(68+w^2-16*w)/(68+w^2+16*w) <\pre>
+
<pre> 4*(68+w^2)/(68+w^2-16*w)/(68+w^2+16*w) </pre>
  
 
----
 
----
 
[[CT_Fourier_transform_practice_problems_list|Back to Practice Problems on CT Fourier transform]]
 
[[CT_Fourier_transform_practice_problems_list|Back to Practice Problems on CT Fourier transform]]

Latest revision as of 12:32, 16 September 2013

Example of Computation of Fourier transform of a CT SIGNAL

A practice problem on CT Fourier transform


$ \ x(t) = e^{-2|t|}cos(8t) $

$ X(\omega) = \int_{-\infty}^{\infty} x(t) e^{-j\omega t} dt \! $

$ = \int_{-\infty}^{\infty} e^{-2|t|}cos(8t) e^{-j\omega t} dt \! $

$ = \int_{-\infty}^{0} e^{2|t|}cos(8t) e^{-j\omega t} dt \! + \int_{0}^{\infty} e^{-2|t|}cos(8t) e^{-j\omega t} dt \! $


after quite a bit of math I get the answer to be


$ \frac{1}{2}(\frac{1}{2 + j8 - jw} + \frac{1}{2 -j8 -jw} + \frac{1}{2 - j8 - jw} \frac{1}{2 + j8 + jw}) $


I'm not sure if I'm right though because when I checked it in matlab the answer I got was

 4*(68+w^2)/(68+w^2-16*w)/(68+w^2+16*w) 

Back to Practice Problems on CT Fourier transform

Alumni Liaison

To all math majors: "Mathematics is a wonderfully rich subject."

Dr. Paul Garrett