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APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY
SEVENTH SEMESTER B.TECH DEGREE EXAMINATION(S), MAY2019

Course Code: EC401
Course Name: INFORMATION THEORY & CODING

PARTA
Answer any two full questions, each carries 15 marks.

Define the term: Amount of information. Find out the information conveyed by
one of the two equally probable messages.
Joint probability matrix of a discrete channel is given by,
P(X,Y)=0.05 0.05 0.02 0.05

0.15 0.16 0.01 0.09

0.12 0.03 0.02 0.05

0.01 0.12 0.01 0.06
Compute marginal, conditional and joint entropies and verify their relation.

Given an AWGN channel with 5 K Hz bandwidth and the noise power spectral density
1/2 510? W/Hz. The signal power required at the receiver is ImW.Calculate the

capacity of this channel.

Given a telegraph source having two symbols, dot and dash. The dot duration is
0.6 sec. The dash duration is half the dot duration. The probability of the dots
occurrence is thrice that of the dash and the time between symbols is 0.1 sec.
Calculate the information rate of the telegraph source.

What is the joint entropy H(X, Y), and what would it be if the random variables X
and Y were independent?
State and establish Kraft’s inequality.

Determine the Huffman coding for the following message with their probabilities
given p(x1) =0.05, p(x2)=0.15, p(x3) 50.2, p(x4) 50.05, p(xs) =0.15, (6) 50.3,
p(x7) =0.1. Find the efficiency and redundancy of the code.
PART ‏تا‎
‎Answer any two full questions, each carries 15 marks.
Draw the bandwidth —SNR trade off graph and explain.

The parity bits of a (7,4) linear systematic block code are generated by
05 = dit+d3+d4
co=d1+d2+d3
c7=d2+d3+d4
(+ sign denotes modulo-2 addition)
where 01, 02, 03 and 04 are message bits and 05, 06, ரே are parity bits. Find generator
matrix G and parity check matrix H for this code. Draw the encoder circuit.

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Duration: 3 Hours

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