EC2301 DIGITAL COMMUNICATION APRIL/MAY 2011 ANNA UNIVERSITY PREVIOUS YEAR QUESTION PAPER
2.Give an advantage and a disadvantage of digital communication.
3.State sampling theorem.
4.What is quantization error?
5.Define hamming distance.
6.What is mean by transparency with respect to line codes?
7.What is a matched filter?
8.Give two applications for eye pattern.
9.Draw the PSK waveform for 011011.
10.What is a non-coherent detection system?
PART B (5*16 = 80 Marks)
11(a)Explain how PWM and PPM signals are generated.
(ii)Explain Binary symmetric channel and Gaussian channel with
their mathematical models. (Marks 10)
12(a)(i)Explain a non-uniform quantization process.
(ii)Write notes on temporal waveform coding.
(ii)Compare various speeches encoding methods.
(13)(a)(i)Assume a (2,1) convolutional coder with constraint length 6.Draw the tree diagram,state diagram and trellis diagram for the assumed coder.
(ii)Find the (7,4) linear systematic block code word corresponding to 1101.Assume a suitable generator matrix.
14(a)Derive the expression for bit error probability due to a matched filter.
15(a)Derive the bit error probability due to coherent ASK,PSK and FSK systems.Compare the performance of these systems.
(b)(ii)Derive the bit error probability due to QPSK receiver.Compare the performance of QPSK receiver with that of PSK receiver.