SPPU Electronics and Telecom Engineering (Semester 6)

Information Theory and Coding Techniques

December 2015

Information Theory and Coding Techniques

December 2015

Solve any one question from Q1 and Q2

1 (a)
Design a Huffman code for a source generating 4 different types of
messages with probabilities 0.3, 0.2, 0.4, 0.1. Find the coding efficiency.

7 M

1 (b)
What are Golay codes? Explain with suitable example.

7 M

1 (c)
Write the procedure for coding of cyclic codes.

6 M

2 (a)
A 3 bit PCM system generates 1000 samples/sec. If the quantized samples are produced by the system with probabilities ( \left { \dfrac {1}{4}, \dfrac {1}{4}, \dfrac {1}{8}, \dfrac {1}{8}, \dfrac {1}{16}, \dfrac {1}{16}, \dfrac {1}{16},dfrac {1}{16}, \right } ) Then find the rate of information. If the samples are equiprobable, what
will be rate of information?

7 M

2 (b)
What are Hamming codes? Explain with suitable example.

7 M

2 (c)
For a (7,4) cyclic code, with generator polynomial g(x)=x

i) 1011

ii) 1110.

^{2}+x^{2}+1, what will be code what for following message words.i) 1011

ii) 1110.

6 M

Solve any one question from Q3 and Q4

3 (a)
Find the generator polynomial for BCH code with codeword length n = 15 and error correcting capability t

_{c}=2.
10 M

3 (b)
Explain Go-Back-N ARQ.

6 M

4 (a)
For a (7,5) RS code, the received codeword polynomid is given as: r(x)=x

^{5}+α^{5}x^{4}+α_{2x3+x2+α6x+a3 where α is element of aF(23). Find the corrected codeword polynomial, if there is single error in the received codeword.}
8 M

4 (b)
Write features of BCH codes.

4 M

4 (c)
What is FEC & ARQ systems?

4 M

Solve any one question from Q5 and Q6

5 (a)
Draw the trellis diagram for following encoder.

8 M

5 (b)
Explain with example polynomial description of convolutional codes.

8 M

5 (c)
Draw the block diagram for coding process Turbo codes.

2 M

6 (a)
Explain Viterbi's algorithm for decoding of convolutional codes.

8 M

6 (b)
Explain generating function for convolutional codes.

8 M

6 (c)
Write any two features of LDPC codes.

2 M

Solve any one question from Q7 and Q8

7 (a)
What are the goals of communication system designer? Explain any three
of them.

6 M

7 (b)
What is Nyquist minimum bandwidth?

4 M

7 (c)
Explain in brief trade off between modulation and coding.

4 M

8 (a)
Explain how coding gain is improved in TCM.

8 M

8 (b)
Write shannon-Hartley capacity theorem. What are its implications?

8 M

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