80

40

0

-40

-80 0 20 40 60 80 100 120

Time (msec)

Am

plitu

de, (

µV)

Xn

Xn+τ

Xn+2τ

t

t

400

200

0.0

-200

400 400

200

0

Xn+τ

-400 -400

-200

0

200

400

-200 Xn

Xn+

2τ

(a)

(b)

100

0

-100

100

0

-100

-100

0

100

Xn+τ, (µV)

Xn+

2t, (

µV)

Xn, (µV)

100

0

-100

-100 0 100

Xn+

τ, (µ

V)

Xn, (µV)

(b)

(a)