Andhra University 2008 B.E Electronics & Tele-Communication Engineering Data Communications - Question Paper

QuestionNo:1 is compulsory and ans any other 4 ques.
All ques. carry equal marks


1)Answer all the ques.
a) Differentiate ranging from unipolar and bipolar format of data transmission'
b) what is the difference ranging from bit rate and baud rate
c) what is cross talk and why does it arise
d) State the purpose of a MODEM in data communications
e) discuss the need for fault correcting codes.
f) provide reasons for using layered architecture in computer networks.
g) provide the control field format of HDLC

2)
a) discuss the different kinds of data transmission lines. explain their merits and demerits
b) discuss briefly the different kinds of transmission errors in data communications system

3)
a) Draw the block diagram of a DPSK modem and discuss its operation
b)with the help of neat block diagram discuss the operation of a TDM system. explain how the synchronization is achieved in transmission and reception

4)
a)Design a single-error correctomg code with a message block size 11 and show by an example that the code can accurate single errors
b)mentin the reasons for the burst errors to occur. discuss and compare the block interleaving and convolution interleaving codes for burst fault correcton

5)
a)Explain the standards used in HDLC transmission.Explain the operating of HDLC protocol with an example
b)Explain the need for flow control in the Data link layer . discuss the sliding window flow control in detail.

6)
a)State the principles of layering for networks. Draw the ISO's OSI model and discuss functions of every layer
b)what is an X.25? explain its protocols in detail

7)
a)Explain the subsequent in relation to packet switched data networks
i)Data gram
ii)Virtual call and
iii)Logical channel
b)Explain the working of a token ring LAN with a neat block schematic diagram.

8)
a)Routing algorithms
b)Packet Assembler and Disassembler (PAD)
c)BISYNC protocol

Earning:   Approval pending.