Laplace Transform and Fourier transform X(s)=x(t)e stdt, est=ee/s2 Since s=σ+j j So o=0-S=jQ2 S-plane frequency domain O X((D)=「x()eoat 少 Fourier transform Fourier Transform is the laplace transform when s have the value only in imaginary axis, sjs 1010   − −  X j = x t e dt j t ( ) ( ) Fourier Transform frequency domain ：  j 0 −  Fourier Transform is the Laplace transform when s have the value only in imaginary axis, s=jΩ Since s =  + j So  = 0 s j =  ( ) ( ) st X s x t e dt   − − =  ， Laplace Transform and Fourier transform s- plane = st j e e e − − −  