RTU 2016 Question Paper Semester VI Information Technology Information Theory and Coding

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B. Tech. Vf-Sem. (Main & Back) Exam.,
ApriUM ay_20!6
rII fnformation Technology
\o 6IT5A Information Theo"y uri Coding

Time: 3 Hours
Maximum Marks: g0
Min. Passing Marks (Main & Back): 26

I nstructions to Candidate s : -

Attempt any five questions, selecting one
questi.on from each unit. All
Questions carry equal marks. Schematii diagrams
must be shown
wherever necessary. Ary data you
feer missins *oy suitabry be assumed
and stated clearly.
Units of quantities used,/ calculated must
be stated clearly.
use of following supporting material is permitted
during examination.
(Mentioned inform No. 205)
1. NIL
2. NIL

Q' l (a) Two binary channel are connected is cascade as shown
is figure below

-

X2 0.8 yz 0.8 22
(i) Find the ones ail channel matrix of the resultant
channel, and draw the
resultant equivalent channel diagram.
t4l
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(ii) Find P (21) and P (z) when P (xr) = P (xz) = 0'5 t4l

(b) Define channel and also explain its types' t8l

OR

Q.1 (a) Define the following
(i) Information t21

(ii) Entropy t21

(iii) Information Rate l2l
(iv) Joint entroPY 121

(b) A discrete source units one of five symbols once every millisecond with
probabilities Il2, ll4 , ll8, 1116 and 1/16 respectively. Determine the source
entropy and information rate. t8l

(xr) = ll2' P(x2) = vt and
Q.2 (a) A DMS X has four symbols x1, x2, x3 and xa with P
p(x3) = p(xa) = 1/8. Construct a shannon fano code for X; show that this code has

the optimum property that e1= L (xi) anci the code efficiency is 100
percent. t8l

(b) Explain Lempel -Ziv algorithm with example' t8l
OR

Q.2 Determine the Huffman code for the following message with their [16]

X1 X2 X3 X4 X5 X6 X1

0.05 0.15 0.2 0.05 0.15 0.3 0.1
the
and also find the average code word length, entropy, code efficiency. Compare
result with entropy.

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UNIT.III
Q.3 (a) What do you mean by linear
block code? Explain.
(b) Given a (7, 4) Iinear brock t4l
code whose generator
matrix is given by
ft oI o o r o rr tt21

Gfo o o o l r ,l
lo o l o r r ol
lo o r o I ,J
(i) Find all the code words
(ii) Find the parity check marrix.
q
Q.3 (a) Differentiatebetween systematic
and non_ systematic codes.
examples.
Also give suitable

(b) Explain the Repeated codes t8l
with an example.
t8I
UNIT.IV
Q'+ (a) For systemafic (7, 4) cycric
code, determine the generator
matrix and parity
check matrix.

Given: G(p)=p3+p+l tl2l
(b) Write a short note on Galois
field polynomial.

(a)
q t4l
Q.4 diagram and explain the
operation of syndrome
calcularor for cyclic
.T;:a"-
(b) Design encoder and decoder t8l
for cyclic codes with brock
diagram.
t8l
UNIT.V
Q.s (a) Explain the viterbi argorithm
and sequential decoding of
(b) convolutional codes.
what are code tree, code trenis [g]
and state diagram for
convolutional encoders?
[g]

[6E6oes]
Page 3 of4

OR
Q.s (a) Explain the difference between convolutional codes
and block codes with
example.
t6I
(b) Draw the state diagram, the tree diagram
and trellis diagram for the convolutional
encoders of figure below.
t5I

(c) Find the free distances of this convolutioonal code.
tsl

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