Telecommunications Question Paper
Telecommunications
Course:Bachelor Of Science In Information Technology
Institution: Kca University question papers
Exam Year:2011
UNIVERSITY EXAMINATIONS: 2010/2011
THIRD YEAR EXAMINATION FOR THE DEGREE OF BACHELOR OF
SCIENCE IN INFORMATION TECHNOLOGY
BIT 4302: TELECOMMUNICATIONS
DATE: APRIL 2011 TIME: 2 HOURS
INSTRUCTIONS: Answer question ONE and any other TWO questions
QUESTION ONE
a) All member states of the International Telecommunication Union (ITU) are required to migrate
from analog to digital terrestrial TV broadcasting technologies by 17th July 2015, and the
Government of Kenya has put in place mechanisms to facilitate the migration. More specifically,
Kenya has opted to embrace the Digital Video Broadcasting – Terrestrial 2 (DVB-T2) standard.
Give FOUR significant benefits that will result from migration to the digital standard. [4 Marks]
b) The local loop or last mile is the telecommunications technology used to connect an enterprise
network to larger networks such as the Internet. You are tasked with selecting such a solution for
your enterprise network.
(i). Identify any FIVE parameters that can be used to compare various local loop technologies.
[5 Marks]
(ii). Compare the following local loop technologies in terms of any FOUR of the FIVE
parameters you have chosen above: Dial-up lines and Modems; ISDN BRI; and ADSL
[6 Marks]
c) Highlight the fundamental differences between a wired telecommunications network and a wireless
telecommunications network. [6 Marks]
2
d) You are tasked with designing the telephone numbering plan for the public switched telephone
network (PSTN) in a newly independent republic. The information needed to tackle the assignment
is captured in Table 1 below:
Table 1. Data for the PSTN in a new republic
Level 1 Exchange
Level 2 Exchange
Level 3 Exchange
Exchange Category Approximate usage
(telephone terminals)
In Thousands
In tens of thousands
Less than one thousand
With the aid of reasonable assumptions, plan the telephone system numbering given the specifications
in Table 1. [8 Marks]
QUESTION TWO
The principal components of a digital telecommunications system used for voice conversations are
source encoding, channel encoding, multiple access, modulation and transmission.
a) Give a brief explanation of the purpose of each stage before transmission. [4 Marks]
b) Give your understanding of converged communications and outline what may be the benefits and
challenges of such communications. [5 Marks]
c) The landing of Optical Fiber connectivity for international Internet connectivity was realized
recently.
(i). Highlight what this connectivity option means to corporate organizations in Kenya. [6 Marks]
(ii). A client server system uses a satellite telecommunications network, with the satellite at a
height of 40,000 km. What is the best-case delay in response to a request? [5 Marks]
QUESTION THREE
a) Identify the components of a basic telecommunications circuit and explain how the components
affect the power transmitted in the circuit. [6 Marks]
b) Identify and clearly explain transmission impairments that have the potential to compromise a
telecommunications signal from a transmitter to a receiver. [6 Marks]
c) Transmission media used in telecommunications cannot have infinite capacity for data transmission.
Explain the basis of this statement. [4 Marks]
3
d) Determine the channel capacity for a teleprinter channel with a 300-Hz bandwidth and a signal to
noise ratio of 3 dB (decibels). [4 Marks]
QUESTION FOUR
VoIP (Voice over Internet Protocol) involves sending voice transmissions as data packets using the
Internet Protocol (IP), whereby the user’s voice is converted into a digital signal, compressed, and
broken down into a series of packets. The packets are then transported over private or public IP
networks and reassembled and decoded on the receiving side. Residential customers can connect to IPbased
networks by using the local loop from the PSTN or high-speed lines, including ADSL/DSL and
cable modems.
(a). Describe the process by which the user’s voice is converted into a digital signal [6 Marks]
(b). Explain the need for compressing the data [2 Marks]
(c). Give a brief description of the ADSL local loop solution [6 Marks]
(d). Give a qualitative comparison of voice over PSTN and voice over IP. [6 Marks]
QUESTION FOUR
a) A simple telephone system consists of two end offices and a single toll office to which each end
office is connected by a 1-MHz full-duplex trunk. Based on your knowledge of the characteristics
of human voice frequency, determine the maximum number of simultaneous voice calls crossing
the trunk. [4 Marks]
b) Give a function for each principal database component in the basic GSM architecture. [4 Marks]
c) State FOUR benefits of bringing digital connectivity through ISDN to the local site. [4 Marks]
d) A user is having a conversation on channel 890.4 MHz (for the GSM 900 system). With the aid of
an appropriate diagram, show the message in the respective slots for both the outgoing channel and
the incoming channel associated with this particular conversation. [4 Marks]
e) Give the full name for the following devices used in an ISDN-network: TE1; TE2; TA; and NT2
[4 Marks]
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