Biju Patnaik University of Technology 2008-8th Sem B.Tech BTech Telematics - Question Paper
Eighth Semester Examination TELEMATICS Full Marks-70
- 2008
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Time: 3 Hours
Answer Question No. 1 which is compulsory and any five from the rest.
The figures in the right-hand margin indicate marks.
Due credit will be given to neatness in answering and drawing suitable figures.
1. Answer in short ot point : 2*10
(a) List the function of Time Slot Interchange unit in a digital telephone system.
(b) Draw the circuit for reducing side tone in a telephone instrument.
(c) List the advantages of a super-heterodyne receiver over tuned radio frequency receiver.
(d) A radio receiver is designed with IF frequency 500 KHz. Determine the oscillator tuning range for receiving signal in the range 555 KHz to 1600 KHz.
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(e) List relative advantages and disadvantages of star and bus topology for computer communication network.
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ii ni ted we stand,., (f) List the advantages of time division multiple access over frequency division multiple access in satellite systems.
(g) Define these terms with respect to satellite orbit :
(a) apogee
(b) perigee
(c) ascending node and
(d) descending node.
(h) List the functions of the Network Layer in OSI mode for ISDN services.
(i) What is constituent of primary rate access for ISDN channel operating at 1.544 Mbs and 2.048Mbps ?
(j) Determine the Doppler frequency of a RF signal at 900 MHz when received in an airplane travelling at 900 Kmph towards the transmitter. The angle of elevation is 20.
2. (a) A telephone exchange has 10000 subscribers. Out of these 100 use the system at any point of time. Calculate the probability of blocking. Assume that each call lasts 3 minutes and each call initiation is independent of other. Assume suitable parameters for all others not specified.
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(b) Analyze the working of a Time Space Time (T-S-T) based telephone switching network. 5
3. (a) With the aid suitable block diagram
discuss the functioning of a super heterodyne receiver. Also mention the typical power levels at each stage and the gain associated with each stage. 5
(b) A radio receiver is designed for receiving frequency range 3 MHz to 20 MH. The IF frequency is 1.8 MHz. Find the range of oscillator frequencies, range of image frequencies. Propose a receiver designed for this purpose so that image frequency can be avoided. 5
4. (a) With aid of suitable block diagram discuss
the working of the communication subsystem inacommunicationsatellite. 5
(b) An earth station for a geo-synchronous satellite system is located at latitude 27N and longitude 37E. The satellite is located at 25 E. Determine the angles in the spherical triangle defied by these points Also determine the range and the look angle. 5
5. (a) Discuss the functions of the data link layer in OSI model. 3
(b) A communication network employs TDM A method of access. 500 users transmit 1000 bit packets of data. The channel bandwidth is 100 MHz and a BPSK is employed. Determine the maximum bit rate allowed per channel. What is the PEEC 5412 5 P.T.O.
packet rate ? How much time is necessary to transmit one packet form each user ? Can this system be used to transmit voice signal from each user. Derive the relationships used. 7
6. (a) Analyze different communication services
supported under ISDN systems. 5
(b) Discuss the process by which data and voice are integrated and transmitted through a common channel in ISDN system. 5
7. (a) Discuss the process involved in setting up
outgoing call in a cellular system. 5
(b) Analyze the effects of multipath fading and Rayleigh fading on the cellular signal.
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(a) OSI model
(b) FM transmitters
(c) Effective Isotropic Radiated power in satellite communication systems
(d) Digitization of voice signal for telephone communication.
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