2
Table of Contents
Chapter 1 1
Chapter 2 41
Chapter 3 77
Chapter 4 117
Chapter 5 144
Chapter 6 182
Chapter 7 205
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CHAPTER 1
P. P. 1.1
2 2
The period is T = = =1
2
x(t + T ) = A cos((2 (t +1) + 0.1 )
= A cos(2 t + 2 + 0.1 )
= A cos(2 t + 0.1 )
= x(t)
Hence x(t) is periodic.
P.P. 1.2
(a) x(t) = t, 0 < t <
T /2 T /2 T / 2 3
E = lim | x(t) |2dt = lim t 2dt = lim 2 =
T → T →
−T / 2 −T / 2 T → 3
1
1
2 T / 2 3
T /2 T /2
P = lim | x(t) |2dt = lim t 2dt = lim =
T → T T → T
−T / 2 −T / 2 T → T 3
i.e. x(t) is neither an energỵ nor a power signal.
(b)
T /2 a
E = lim
T →
| x(t) |2dt = lim
T → A dt = 2aA
2 2
−T / 2 −a
i.e. x(t) is an energỵ signal.
(c ) | x(n) |= 5 | e− j4n |= 5
N N
| x[n] | 5
1 1
P = lim 2
= lim 2
N → 2N +1 n=− N N → 2N +1
n=− N
1
= lim 25(2N +1) = 25
N → 2N +1
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i.e x[n] is a power signal.
P.P. 1.3
(a) ze = t 2 −10, zo = 4t
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1
h (t) = [u(t +1) − u(t −1)]
(b)
e 2
1
h (t) = [−u(t +1) + 2u(t) − u(t −1)]
o
2
These are sketched below. ho
he
½ 1/2
t 0 1 t
-1 0 1
P. P. 1.4
(a)
−
sin(t3 + / 2) (t)dt = sin(t3 + / 2) t = 0 = sin( / 2) = 1
10
(b)
(t 2 + 4t − 2) (t −1)dt = (t 2 + 4t − 2) t = 1 = 1+ 4 − 2 = 3
0
P. P. 1.5
0, t0
i(t) = 10, 0t 2
−10, 2t 4
i(t) = 10u(t) − u(t − 2) −10u(t − 2) − u(t − 4)
= 10[u(t) − 2u(t − 2) + u(t − 4)]
t
Let I= idt
−
For t < 0, I = 0.
t
For 0 < t < 2, I = 10dt = 10t
0
2 t
t
For 2 < t < 4, I = 10dt − 10dt = 20 −10t = 40 −10t
0 2 2
4
For t > 4, Thus,
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