UNIV4VINU | ENGINEERING ACHIEVERS

B.E./B.Tech. DEGREE EXAMINATION,

Fourth Semester

Information Technology

IF 252 — TELECOMMUNICATION SYSTEMS

Time : Three hours Maximum : 100 marks

Answer ALL questions.

PART A — (10 x2 = 20 marks)

1. What is modulation index?

2. What is fading?

3. What is a Telepoint System?

4. What is Half Duplex?

5. What is a Geo Synchronous satellite?

6. What are Azimuth and Elevation angles?

7. What is a Graded Index Fibre?

8. What is WDM?

9. What is a DTMF System?

10. What is GSM and TDMA?

PART B — (5 x 16 = 80 marks)

11. (i) Define Sensitivity and Selectivity of a receiver. (4)

(ii) What is Image Frequency? Explain. (6)

(iii) Draw the block diagrams of FDM Transmitter and Receiving End. (6)

12. (a) (i) Explain the operation of a cordless telephone. (6)

(ii) Explain in detail the operation of an advanced Mobile Phone System. ( 10)

Or

(b) (i) Draw the block diagram of an Analog Cell Phone. (6)

(ii) Explain in detail the operation of a Cellular Radio System. (10)

13. (a) Write a detailed note about Satellite Orbits and Geo-Synchronous Satellites.

Or

(b) Explain in detail an Earth Station, with a neat block diagram.

14. (a) Explain in detail the various types of fiber optic cables, its construction and its

characteristics.

Or

(b) Explain in detail the optical transmitters and receivers used in Fiber Optical

Communication.

IF 252 — TELECOMMUNICATION SYSTEMS

Time : Three hours Maximum : 100 marks

Answer ALL questions.

PART A — (10 ? 2 = 20 marks)

1. Draw clearly block diagram of superheterodyne receiver and give its frequencies.

2. What is gain of an antenna? Give its relationship.

3. Explain frequency reuse concept in mobile communication and give the relation for

frequency reuse distance.

4. What are the advantages of digital cellular systems?

5. Enumerate the various subsystems in satellite.

6. Enumerate the different types of orbits in satellite communication.

7. What are signal bandwidth limitations?

8. Enumerate the different types of fibers.

9. What are ISDN and DSL in telephone system?

10. Give the parameters for CT2 cordless telecommunication system.

PART B — (5 ? 16 = 80 marks)

11. (i) Explain, with diagrams, the amplitude–modulated transmitter oper ation.

(ii) Derive, from basic principles, the expression for received power in free space

propagation.

12. (a) (i) Explain, with block diagrams, the working of AMPS with relevant

specifications.

(ii) Explain digital cellular system with relevant specifications.

Or

(b) Explain, with relevant specifications, the services and features of cordless

telephone (CT2) system.

13. (a) (i) State and explain Kepler’s laws.

(ii) Discuss the importance of satellite transponder with relevant diagram.

Or

(b) (i) Explain the salient featur es of DBS TV satellite communication.

(ii) Explain, with diagrams, the Cassefrainion antenna used in earth station complex.

Discuss its parameters.

14. (a) (i) Discuss the features of attenuation and dispersion of glass fibers.

(ii) Draw clearly fiber optic communication system and discuss its constituent blocks.

Or