Get premium membership and access revision papers, questions with answers as well as video lessons.
Tlcm 122: Telecommunications Fundamentals I Question Paper
Tlcm 122: Telecommunications Fundamentals I
Course:Bachelor Of Telecommunication And Information Engineering ()
Institution: Kabarak University question papers
Exam Year:2011
KABARAK UNIVERSITY
UNIVERSITY EXAMINATIONS
2011 ACADEMIC YEAR
FOR THE DEGREE OF BACHELOR OF TELECOMMUNICATIONS
TLCM 122: TELECOMMUNICATIONS FUNDAMENTALS I
DAY: FRIDAY DATE: 16/12/2011
TIME: 9.00 – 11 .00 A.M. STREAM: Y1S2
INSTRUCTIONS:
• Answer ALL questions in PART ONE and any TWO questions in PART TWO
PART ONE
Question One (30 marks)
a. Name and describe the two technologies used to implement circuit switching. (3 marks)
b. Using a diagram explain, in detail, the operation of a carbon based microphone. (4 marks)
c. Describe two functions of the control subsystem of a public switched telephone network
(PSTN) exchange. (3 marks)
d. Describe in detail how the number of crosspoints in a single stage (simple) crossbar
switch can be reduced while still keeping it non blocking. (4 marks)
e. Under what circumstances would the exchange of a public switched telephone network
(PSTN) send a busy tone to a subscriber immediately when they pick up their telephone
to make a call? (2 marks)
f. Using a diagram and a switching example, describe how a time slot interchanger (TSI)
switch works. (6 marks)
g. A TSI switch is used to switch 8 digital signals each with a bit rate of 3200bps. The
duration of a time slot is 2 milliseconds. Calculate the minimum size of each of the
memory locations used on the TSI. (3 marks)
h. Describe
i. Pulse dialing. (2 marks)
ii. Two disadvantages of pulse dialing. (3 marks)
PART TWO
Question Two (20 marks)
a. Describe
i. Frequency modulation. (2 marks)
ii. Phase shift keying. (2 marks)
b. An analog signal, with frequency components between 250Hz and 5500Hz is used to
amplitude modulate a carrier with a frequency of 100KHz. Determine the lowest and
highest frequency components of the modulated signal. (3 marks)
c. Is frequency division multiplexing an analog or digital process? Explain your answer.
(2 marks)
d. Describe why
i. Synchronization important in time division multiplexing, and describe one method used
to implement synchronization in time division multiplexing. (4 marks)
ii. Frequency division multiplexing is more expensive to implement than time division
multiplexing. (3 marks)
e. Twenty analog signals each with frequency components between 450Hz and 5600Hz are
first filtered with low pass filters, each with a cutoff frequency of 4800Hz, and then the
filtered signals are frequency division multiplexed using a guard band of 500Hz. If the
multiplexing process uses amplitude modulation, calculate the bandwidth of the
multiplexed signal. (4 marks)
Question Three (20 marks)
a. Define
i. Line coding (2 marks)
ii. An oscillator (2 marks)
b. Encode the following binary data 1001101011001101 using Manchester code. (4 marks)
c. Describe basic rate interface integrated services digital network (BRI-ISDN). (3 marks)
d. What is the difference between how synchronization is implemented in a T1 carrier
system as compared to the way it is implemented in an E1 carrier system? (3 marks)
e. Describe three advantages of digital transmission as compared to analog transmission.
(6 marks)
Question Four (20 marks)
a. Describe two ways in which a transmission channel modifies a signal transmitted on it.
(3 marks)
b. Define quantization noise. (2 marks)
c. An analog signal with frequency components between 245Hz and 9876Hz is digitized
using pulse code modulation (PCM). The PCM process uses 198 quantization levels.
The resultant digital signal is then transmitted using one DS0 (digital service 0).
i. Calculate the maximum rate at which the analog signal can be sampled. (4 marks)
ii. Is the digitization process accurate? Explain your answer. (2 marks)
d. What is a transducer? Give two examples of transducers used in telephone networks.
(3 marks)
e. Describe two advantages of active filters as compared to passive filters. (4 marks)
f. Define the cutoff frequency of a practical lowpass filter. (2 marks)
More Question Papers
Popular Exams
Return to Question Papers