5 The discrete-time Fourier transform
5.0 Introduction
(1) Fourier series (periodic signal)
5,The Discrete time Fourier Transform


Nn
nNjk
k
Nk
nNjk
k
enx
N
a
eanx
)/2(
)/2(
][
1
][
(2) Fourier transform (aperiodic signal)


nj
N
j
njj
enxeX
deeXnx


][)(
)(][
2
5 The discrete-time Fourier transform
Fourier series (periodic signal)
x[n]
ak
5 The discrete-time Fourier transform
Fourier transform (aperiodic signal)