F
N
f
n
= Ae
αn
cos(2πωn + φ),
ω ∈ [0, 1/2] φ ∈ [0, 2π) T = 1/ω
ω ∈ (0, 1/2)
ω ∈ (0, 1/2) L ≥ 2 N ≥ L +1
ω α
α ≤ 0 L, K → ∞
ω = 1/2
ω = 1/2 sin φ 6= 0 f
n
(−e
α
)
n
L
(ω = 0)
ω = 0 cos φ 6= 0 f
n
e
αn
N L
α
(α = 0)
ω < 1/2
ω = 1/2
ω ω < 1/2 K L T = 1/ω
Lω Kω
π/2
C cos(2πωn +
e
φ) C sin(2πωn +
e
φ)