Chapter 4 Fourier transform Fourier transform pair factor x() J X(o)elon do Synthesis equation 2丌J-∞ X(o)=丁 x(te Ja t dt Analysis equation 1. A linear combination of complex exponentials 2.x(o)- Spectrum(频谱)ofx() x()<"→X(io) 55 Chapter 4 Fourier Transform ( ) ( ) j t X j x t e dt   + − − =  ( ) ( ) 1 2 j t x t X j e d     + − =  Synthesis equation Analysis equation Fourier Transform Pair 1. A linear combination of complex exponentials. factor 2. X(j) ——Spectrum（频谱） of x(t) x(t)⎯→X(j) F