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Code No:C9305JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD

M.Tech I SEMESTER EXAMINATIONS, APRIL/MAY-2013

ADVANCED DATA COMMUNICATIONS

(SYSTEMS AND SIGNAL PROCESSING)

Time: 3hours Max.Marks:60Answer any five questions

All questions carry equal marks

- - -

1. If a binary data is to be transmitted using the following modulation schemes, give

the procedure to generate modulated, and demodulated signals for each scheme toretrieve the original data in AWGN channel conditions:

a) 8-PSK b) 8-QAM

2.a) What are the primary functions of UART (Universal Asynchronous Receiver

Transmitter)?b) With suitable block diagram(s), explain how the information is transferred

between Data Terminal Equipment (DTE) and (Data Communication Equipment

(DCE).

3. Describe the mechanical, electrical, and functional specifications of RS-232 serialinterface standard.

4.a) Discuss about various types of error detection methods available in data

communication.

b) For a 12-bit data string of 101100010010, determine the number of Hamming bits

required arbitrarily place the Hamming bits into the data string. Also determinethe logic condition of each Hamming bit. Assume an arbitrary single bit

transmission error, and prove that the Hamming code will successfully detect theerror.

5.a) With suitable frame format, discuss about SDLC synchronous protocol. Alsoexplain what is meant by transparency?

b) Determine the bit pattern for the control field of a supervisory frame sent from a

secondary station to the primary for the following conditions: (i) Secondary is

ready to receive (ii) it is a final frame (iii) Secondary is confirming correctreception of frames 3, 4, and 5.

6.a) With suitable sketches, explain the following:i) circuit switching

ii) packet switching, and

iii) datagram.

b) For the European E1 32 channel system with number of bits per frame is 256 and

number of bits in the synchronizing word is 8, and a 2.048 Mbps transmission

rate, determine the average number of bits needed to synchronize and the average

synchronization time.

R09

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7.a) Give the comparison between FDMA, TDMA, and CDMA with suitable

examples.

b) Explain the terms: polling, and token passing.

8. Write the following:

a) CSMA/CA

b) Sliding window protocol.

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