UNIVERSITY EXAMINATIONS: 2018/2019
EXAMINATION FOR THE DEGREE OF MASTERS OF SCIENCE IN
DATA COMMUNICATIONS
MDC 6206: ADVANCED TELECOMMUNICATION
ORDINARY EXAMINATIONS
DATE: AUGUST, 2019 TIME: 2 HOURS
INSTRUCTIONS: Answer Question One & ANY OTHER TWO questions.
Instructions
Answer Question 1 in Section A and Any Other two Questions from Section B, You may
use the following if need be:
Length of dipole antena=λ/4
=c/4ν,where symbol has their usual meaning.
Modulation index ma=Em/Ec
= (Emax-Emin) /(Emax+Emin)
Maximum coverage range of antenna d=√2hR
Maximum Los distanced=√2RehT+√2RehR
QUESTION ONE (20 MARKS)
a) Discuss a Telecommunication medium giving the various telecommunication medium in
use today. (4 Marks)
b) Discuss the Trends Driving Data Communication (6 Marks)
c) Discus the Cellular systems generations clearly showing their various examples
(6 Marks)
d) Describe the setting up a call process (4 Marks)
QUESTION TWO (15 MARKS)
a) Describe the four basic elements of any Telecommunication system and name the basic
units of a Telecommunication system. (4 Marks)
b) Identify the parts X and Y in the following block diagram of a generalised communication
system?
(3 Marks)
c) Explain the functional description of digital communication system in detail.
(8 Marks)
d) Discuss the advantages and disadvantages of Digital Communication
(6 Marks)
QUESTION THREE (15 MARKS)
a) What causes ‘fading’ in a radio channel and how does it affect digital transmissions?
Explain the difference between ‘flat’ fading and ‘frequency-selective’ fading and state
what is meant by the ‘coherence bandwidth’ of a channel.
(5 Marks)
b) Compared to analogue techniques, what do you consider to be the three main advantages
of digital voice transmission in wired and wireless telephony?
(3 Marks)
c) Explain the difference between ‘waveform coding’ and ‘parametric coding’ for speech in
telephony. What features of speech and its perception are exploited by the G711 64 kb/s
standard coder for wired telephony to achieve acceptable speech quality at the required bitrate.? (7 Marks)
QUESTION FOUR (15 MARKS)
a) Explain the term asynchronous as applied to digital transmission and Describe one
commonly used asynchronous technique and its main applications.
(5 Marks)
b) What are the main requirements for PCM wave-forms used for the synchronous
transmission of digital signals over wired links in telephone networks?
(5 Marks)
c) What causes ‘fading’ in a radio channel and how does it affect digital transmissions?
Explain the difference between ‘flat’ fading and ‘frequency-selective’ fading and state
what is meant by the ‘coherence bandwidth’ of a channel.
(5 Marks)
X Transmitter Y Receiver
