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75. What are the advantages and disadvantages of convolutional codes?
76. Explain about the Viterbi decoding method with an example.
77. (a) What is meant by random errors and burst errors? Explain about a coding
technique which can be used to correct both the burst and random errors simultaneously.
(b) Discuss about the various decoders for convolutional codes.
78. Draw the state diagram, tree diagram for K=3, rate1/3 code generated by
79. (a) Design an encoder for the (7,4) binary cyclic code generated by g(x) = 1+x+x 3 and verify its
operation using the message vector (0101).
(b) What are the differences between block codes and the convolutional codes?
80. Explain various methods for describing Conventional Codes.
81. A convolutional encoder has two shift registers two modulo-2 adders and an output multiplexer.
The generator sequences of the encoder are as follows: g (1) =(1,0,1); g (2) =( 1,1, 1). Assuming a
5bit message sequence is transmitted. Using the state diagram find the message sequence when
the received sequence is
(11,01,00,10,01,10,11,00,00,......)
82. (a) What is meant by random errors and burst errors? Explain about a coding technique which
can be used to correct both the burst and random errors simultaneously.
(b) Discuss about the various decoders for convolutional codes.
83. Find the output codeword for the following convolutional encoder for the message sequence
10011. (as shown in the figure).
84. Construct the state diagram for the following encoder. Starting with all zero state, trace the path
that correspond to the message sequence 1011101. Given convolutional encoder has a single shift
register with two stages,(K=3) three modulo-2 adders and an output multiplexer. The generator
sequence s of the encoder are as follows. g(1)=(1, 0, 1) ; g(2)=(1, 1, 0),g(3)=(1,1,1).
85. Draw and explain Tree diagram of convolutional encoder shown below with rate=1/3, L=3