Fourier Transform Solved Examples


In this section, we will learn to find FT of some basic functions. Fourier transform properties are used in certain cases.


(1) x(t)=e-atu(t)  , a>0


By definition,

(2) x(t)=eatu(-t)  , a>0

By definition, 
     

Using time reversal property of fourier transform is another method to solve.


(3) x(t)=e-a|t|  , a>0

By definition,


(4) Fourier transform of unit Impulse function

x(t)= δ(t)

Fourier transform of unit Impulse function


By definition,    
fourier transform of delta (unit impulse) function

(5) Fourier transform of rect function  





fourier transform of rectangular pulse




(6) Fourier transform of signum function

X(t)=Sgn(t)

Sgn(t) = 1 , t>0
 = -1 , t<0

By definition,  


(7) Fourier transform of unit step function    


x(t)=u(t) 

fourier transform of unit step

(8) x(t)=1

Using duality property of fourier transform.


fourier transform of sine cosine


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