.
1. (white noise, WN)
σ2, .. {Z t } ~ WN (0, σ2), γ(0) = σ2 γ(h) = 0 | h | > 0. , (5.20), 젠
. (5.22)
, , .
.5.2
2. AR (1)
Xt = Xt - 1 + Zt, { Zt } ~ WN (0, σ2), (2.7) , , = 0, 1, 2, . , (5.20) (1.447) [4],
.5.3 R (1) = 0,8 = - 0,8 0 ≤ ω ≤ π .
) = 0,8
) = - 0,8
.5.3 R (1) ( - =0,8; - = - 0,8)
, .5.3, , . > 0 - - . , = 0,8 R (1) , , . ( 2, .2.2). , < 0 , , . , π. , , ( .2.9 2.12 2).
→1 R (1) Xt = Xt - 1 + Zt.
(5.24)
, , . , (5.24) , "" , ω = 0, .
|
|
3. (1)
(2.20), (1),
Xt = at + θ1 t 1. (2.20)
Xt = Zt + θ Zt 1, { Zt } ~ WN (0, σ2).
(1) (. (2.22):
(5.20) , R (1),
(5.25)
.5.4 (1) θ = 0,8 θ = - 0,8. (1) θ. , .
)
)
. 5. 4 (1) ( - θ = 0,8; - θ = - 0,8)
, θ > 0 , (1) . , θ < 0 , (1) .
4.
,
(5.26)
ω0 - (0,π); φ - , [0,2π].
, φ - , (5.26) .
, h . , (5.26) " " . ω0.
E (Xt) = 0, V r (Xt) = E (Xt 2) = 1/2,
, : V r (Xt) = γ (0) = 1/2. , ω0. , , , ,
, ω = ω0. , (5.26) ω0.
5.
,
(5.27)
ω0 , φ , (5.26); Zt - .
(5.27)
h, Xt . F (ω) (5.27) . ω0, F (ω), . F (ω) F 1(ω) F 2(ω) ,
|
|
F 1(ω) - ; F 2(ω) - .
, F 1(ω) , F 2(ω) - . , cos(ω0 t + φ)
Zt ,
(5.22).
, (5.27)
, , ω0, .