Pune University BE Electronics Advanced Communication System Question Papers

Pune University BE Electronics Advanced Communication System

Question Papers

B.E. (Electronics) ADVANCED COMMUNICATION SYSTEM (2008 Pattern)

(Elective – IV) (Sem. – II)

Time :3 Hours]                                                                           [Max. Marks :100

Instructions to the candidates:-

1)            Answer three questions from each section.

2)            Answers to the two sections should be written in separate answer books.

3)             Neat diagrams must be drawn wherever necessary.

4)             Pigures to the right indicate full marks.

5)             Use of logarithmic tables, slide rule, Mollier charts, electronic pocket calculator and steam tables is allowed.

6)            Assume suitable data, if necessary.

SECTION – I

QI) a) Describe the operation of cellular system.                                                             [8]

b)            Explain each of the following in brief.                                                           [6]

i)              Frequency Re-use schemes.

ii)           Hand-off mechanism.

c)            Explain Fading effect due to delay spread.                                                   [4]

OR

Q2) a) Define the term Co-channel interference reduction factor? How CCIR can be calculated. Explain.                                                                                                                [8]

b)            State and Explain formula for mobile radio propagation between fixed stations.        [6]

c)            Write short notes on long distance propagation.                                          [4]

QQA a) What is Beam width? Explain relationship between gain and beamwidth. [8]

b)            What is the need of ‘Handoff in mobile communication’? What are the different types of handoff methods used? Explain.                                                                          [8]

OR

Q4) a) Design of directional antenna system for K = 7 cell pattern.                             [8]

b) Explain the following terms:                                                                                                                             [8]

i)              UHF – TV interference.

ii)            Space diversity antennas.

 

Q5) a) What is cell splitting? What are the different types of cell splitting? Explain.

[8]

b) Explain in detail Microcells.                                                              [8]

OR

Q6) a) Draw the GSM Architecture and explain its various elements.                         [8]

b)            Write short notes on Narrow beam concept.                                       [4]

c)            Explain the Handover mechanism in GSM.                                        [4]

SECTION – II

Q7) a) Explain briefly various look angles for satellite earth station.                           [8]

b) Explain in detail telemetry, Tracking commands and Monitoring System. [8]

OR

Q8) a) The earth subtends an angle of 17 when viewed from geostationary orbit.

What are the dimensions and gain of a horn antenna that will provide global coverage at 4 GHz?                                                                                                             [4]

b)            Explain the following terms:                                                                  [8]

i)             Power System

ii)           Attitude and orbit control system.

c)            List the advantages of Geostationary Satellite.                                   [4]

Q9) a) Write a note on Telephony and Television signals.                                             [8]

b)            Explain the meaning of Noise temperature of receiver. With the help of overall noise model of the receiver derive the expression for effective system noise temperature Ts for the receiving earth stations. [10]

OR

Q10)a) Calculate the Noise Temperature @Ts) of a 8 GHz receiver, which has different gains and noise temperatures as given below.                                                         [6]

T. =in

50k

T =RF

: 50k

Grf =

23db

T =M

500k

GM =

0db

T =IF

1000k

GIF =

30db

 

b)            Explain the terms:                                                                                               [8] i) C/N ratio ii) G/T ratio

c)            Compare the BPSK and QPSK system.                                                         [4]

Qll)a) Explain the necessity of multiple access techniques.                                           [4]

b)            Write a short note on CDMA.                                                                          [6]

c)            Explain TDMA.                                                                                                  [6]

OR

Ql2)a) With a neat schematic of a VSAT/WLL communication network explain how a GEO satellite is used to link a large number of VSATs. [8]

b) Explain the terms with respect to VSAT.                                                                                               [8]

i)             Link Budget.

ii)           Free – space path loss.

iii)        Noise Band width.

iv)         Edge of coverage loss.

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