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x(t) t
x(n) n
t
t
f = 1/T
x(t)=cos(2 *f0*t + ) => f0
ntTtntTA
ntTtntTA
A
-A T/2 t
f
|Xn|
nA n=±1,±5,…
Xn= na - nA n=±3,±7,…
0 ( n )
nT2TtnT20
nT2tnT2A
2
T t
-2
t
tnTtn
T
f
fT1
TnfT
1T1
n
ofT f
|Xn
X
TnTn
TA
TncT
A
X(f) =F x t = ttx ft
x t F-1{ X(f) } = ffX ft
x t = n
tnfnX
Xn = ttxT
T
T
ftT
txTT
x t
t
x t x t
t
x(t)
t
T
T
tfkTk
k ttxTXf
X
f = 1/T f
nf = n/T f
x t = txTT
ffX ft
X f
réponse forcéey(t)
x(t) 0 y(t)
x(t) réponse globale
terme transitoireterme de régime
y t x t .
y t x1 t y t x2 t
a y1 t + b y2 t a x1 t + b x2 t
invariant dans le temps
y t x t
y t - = x t -
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