Chapter 1
Introduction to Data Communications
True-False Questions
The following are possible True/False questions for tests. The statement is given and the answer
is provided in square brackets. The level of difficulty (easy, moderate, difficult) and the

Chapter 2
Application Layer
True-False Questions
The following are possible True/False questions for tests. The statement is given and the answer
is provided in square brackets. The level of difficulty (easy, moderate, difficult) and the page
number(s) re

Two pulse waveforms a:(t) and y(t) are shown in Fig. P—4.6.2. Determine and sketch 136(7),
ry(7'), and r$y(7').
x(t) y(t)
t t
Figure 20: P-4.6.2
The autocorrelation functions below are zero outside of the intervals given.
a)
1
rm(7') : dt : 1 + 7', for —

The power spectrum of the output signal due to 121 is equal to,
IH1(w)l25v1(w) = (2/7T)|H1(w0)l25(w ‘ we) + (2/7T)H1(—w0)5(w + WU)
Due to the symmetry of H1(w), we have,
|H1(w)|23u1(w) = (2/7T)|H1(wo)|2[5(w - we) + 5(w + wo)l
The transfer function from ’0

a)
N, = 2(n/2)B = 2 X 10—6(104) = 0.02 W (255)
S,- : ¢2(t) = (3)2(1/2)+(1/2)(1/2)=4.75W (256)
Si
E = 237.5 (23.8 dB) (257)
b) After LPF
eo(t) = (1/2) c0s(10007rt) (258)
so = ext) = <1/2>2(1/2> = 1/8 (259)
(260)
Using Eq. (5.72), N0 = Ni/4 = 0.005 and

a.) Total dissipated energy is given by:
E = |f(t)|2dt] /R = 2 tze"2tu(t)dt = 2 foo tze_2tdt = 0.5J.
O
b.) The fourier transform of the signal is given by:
10
F“) = W
Recall that the Energy of the voltage signal f(t) with Fourier transform F(w) in the fre

Problem 3.1.1
a) Determine the function f (t) whose Fourier transform is shown in ﬁgure P—3.1.a.
b) Determine the function f (t) whose Fourier transform is shown in ﬁgure P—3.1.b.
c) Sketch f (t) and g(t) near t = 0. What effects does the phase has on the