Answers to Problems in Random Data
CHAPTER 1
1.1 Period = 2π
1.2 (a) and (c) are periodic; (b) and (d) are nonperiodic
1.3 The autocorrelation function as τ → ∞
1.4 Variance = 0.09
1.5
1.6 (d) is always true
1.7 (c), (d), and (e) are always true
1.8 (a) or (b)
1.9 (b) and (c)
1.10 Only (b) now applies
CHAPTER 2
2.1 f (x) = x|x|
f (x1 + x2) = (x1 + x2)|x1 + x2| ≠ x1|x1| + x2|x2|;
f (cx) = cx|cx| ≠ cx|x|
2.2 f (c1x1 + c2x2) = c1f (x1)+c2f (x2)
2.3 (a) and (b)
2.4
2.5 (a)
(b)
(c)
(d)
2.6 For τ < 0, h(τ) = 0; for τ ≥ 0,
2.7 From Equation (2.24),
The maximum response occurs where
This requires ...