The Hong Kong Polytechnic University
Department of Electrical Engineering
Telecommunication Laboratory
Pulse Code Modulation (PCM)
Objectives:
To study 2-channel time division multiplexing and sampling of analog signal and
its pulse code modulation in the

Digital Transmission
Objectives
To introduce a binary digital transmission system
To explain intersymbol interference and the condition of zero intersymbol interference, and to
show how to evaluate system performance by use of an eye diagram
To discuss

Exercise solution (Digital Communications)
1.
p (t )
1 cos
2(
2 t
T
t 2
)
T
2 t
2
2 t
2 t
sin
sin
T lim T
T lim
T 1
p (0) lim
t 0
t 0
t 0
t 2
t
t
2( )
4 ( )
2( )
T
T T
T
1 cos 2n
p (nT )
0,
n0
2(n )2
1 cos
The zero ISI condition can be satisfied.
2. C

Optical Fiber Communications
Objectives
To introduce optical fiber communication system and discuss its key advantages
To introduce main light sources in optical fiber communication system and explain their operation
principles
To illustrate light prop

Exercise solutions (Optical Fiber Communications)
1. Suppose a laser diode radiates red light with wavelength of 650nm. What is the energy of a single
photon?
Solution
Ep = hf = hc/
= (6.6 10-34 3 108)/650 10-9 = 3.04 10-19 J
2. Assume you have a glass ro

Telecom homework (pulse modulation 1)
1. For a message signal m(t) = cos(0t) + cos(0t)cos(20t), draw its spectrum and
determine the minimum sampling frequency required in a PAM system.
2. Two communication channels in a PAM system can handle 0 - 8 kHz and

Telecom homework Digital communications
1.The impulse response of a transmission channel is given by
1 sin(4 106 )t
h(t ) =
106 t
(i) Determine the channel bandwidth.
(ii) A set of rectangular wave pulse trains with period of 2 s and pulse duration of 1 s

Telecommunication Fundamentals
EE 3801 EE 3131
Subject Lecturer: Professor Wei Jin, CF 630
eewjin@polyu.edu.hk
Alan Pak Tao Lau, Assistant Professor, CF 608
eeaptlau@inet.polyu.edu.hk
Laboratory Experiments:
The experiments will be performed in the Contro