Anna University Chennai 2005 B.E TELECOMMUNICATION SYSTEM & SERVICES - Question Paper
Sunday, 24 February 2013 12:20Web
Code: A-17 Subject: TELECOMMUNICATION SYSTEM & SERVICES
Time: three Hours Max. Marks: 100
NOTE: There are 11 ques. in all.
ques. one is compulsory and carries 16 marks. ans to Q. 1. must be written in the space given for it in the ans book supplied and nowhere else.
ans any 3 ques. every from Part I and Part II. every of these ques. carries 14 marks.
Any needed data not explicitly given, may be suitably presumed and said
Q.1 Choose the accurate or best option in the following: (2x8)
a. Equipment that controls the electrical termination of ISDN at the user's premises is called
(A) NT1. (B) NT2.
(C) NT3. (D) NT4.
b. A device that links 2 homogeneous packet broadcast local network is
(A) HUB. (B) Repeater.
(C) Gateway. (D) Bridge.
c. In a telephone network call waiting feature requires 2 switching paths to be set up simultaneously and both the paths must use
(A) various signalling scheme.
(B) identical signalling scheme.
(C) 2 orthogonal signalling scheme.
(D) 2 signalling scheme with improper phase delay.
d. Which 1 of these can have the highest data transfer speed :
(A) ISDN. (B) DSL.
(C) Cable Modem. (D) VSATs.
e. DQDB is an acronym for ________________.
(A) Distributed Queue Database.
(B) Differential Queue Database.
(C) Data Queue Dual Bus.
(D) Distributed Queue Dual Bus.
f. In ___________, every packet of a message need not follow the identical path from sender to receiver.
(A) Circuit Switching.
(B) Message Switching.
(C) Virtual Approach to Packet Switching.
(D) Datagram Approach to Packet Switching.
1
Index Next>>g. The signal to noise ratio for a voice grade line is 30.1 dB or a power ratio is 1023 :1. The maximum achievable data rate on this line whose spectrum ranges from 300 Hz to 4300 Hz is
(A) 6200 bps. (B) 9600 bps.
(C) 34000 bps. (D) 31000 bps.
h. Which transmission mode is used for data communication along telephone lines?
(A) Parallel (B) Serial
(C) Synchronous (D) Asynchronous
PART I
ans any 3 ques.. every ques. carries 14 marks.
Q.2 a. Explain common channel signalling scheme (CCS) and CCS message format for 3 unit message. (7)
b. Briefly discuss the subsequent :
(i) Cross talk.
(ii) D-conditioning.
(iii) Jitter.
(iv) Impulse phase hit. (7)
Q.3 a. What is the purpose of an Echo-suppressor? Why is it necessary for successful data communication? Which forms of data communication - simplex, half duplex or full duplex is not useful with an enabled echo suppressor? (6)
b. Briefly discuss the subsequent : (8)
(i) Concentrator.
(ii) Subscriber's loop.
Q.4 Explain in detail the subsequent :
(i) Video & Voice response systems.
(ii) Wired Home and Paperless office. (7)
(7)
Q.5 a. Explain with proper block diagram the principle of operation of modern telephone system. discuss frequency characteristics of DTMF. (8)
b. In a packet switched network circuit determine the packet size which minimizes the total delay. (6)
Q.6 a. Derive an expression for the blocking probability of a TSTS switch if every stage is individually non blocking. (5)
b. What is ALOHA? Derive the expression for the throughput of a slotted ALOHA. (9)
2
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ans any 3 ques.. every ques. carries 14 marks.
Q.7 a. What is the purpose of a scrambler and descrambler circuit? discuss the operations of these circuits. (8)
b. What kinds of digital circuit is used as a bit splitter? elaborate the advantages and disadvantages of a 16 QAM modulator vis-à-vis a 16 PSK modulator? (6)
Q.8 a. With a neat block diagram discuss Ethernet Interface Adapter. (6)
b. How does CSMA/CA differs from CSMA/CD? discuss the fast Gigabit Ethernet. What is the chief use of Gigabit Ethernet? (8)
Q.9 In a local area network there are workstations and personal computers.
(i) Show the distribution of MTA and UA in this environment.
(ii) How would the message exchange take place ranging from 2 personal
computer and a workstation? (7)
(7)
Q.10 a. Describe with diagram the design of Cellular Radio telephone system. (9)
b. Discuss advantages of cellular mobile radio telephone services over the PSTN telephone services. (5)
Q.11 Write short notes on any 2 of the subsequent :
(i) FAX.
(ii) Cable TV.
(iii) X.25 protocol. (7 + 7)
| Earning: Approval pending. |
