Engineering BE Electronics and Computer Science Sem 5 December 2019 2019 Digital Communication Question Paper - Mumbai University | munotes

Questions asked in this paper

• (4) Figures to the right indicate full marks

1. Q1 Answer the following (Any Four) 20 marks
   • a. Define the following terms and give their significance (i) Mean (ii) Central moment (ii1)
   • b. What is Entropy of an information source? When is entropy maximum?
   • c. Compare intersymbol interference and interchannel interference
   • d. Differentiate between QPSK and OQPSK
   • e. Compare optical fibre with coaxial cable and twisted pair cable
   • a) Explain with neat diagram transmitter, receiver and waveforms the BPSK modulation System. Sketch signal space diagram and PSD of BPSK. 10
   • b) A discrete memory less channel has an alphabet of six symbols, with the probabilities as Construct the Huffman code and find entropy and average code word length of code Also calculate the code efficiency and redundancy of the code 10
   • a) Linear block code having following parity check equations — 1)G & H matrix li) error detection, Correction capacity of the code;
   • iii) decode the received codeword-------101100 10
   • b) Discuss the problem of inter symbol interference (ISI). Explain the measures to be taken to reduce ISI. How to study ISI using eye pattern? 10
   • a) Explain the working of Minimum Shift Keying, modulator and demodulator, with the help of block diagram and waveforms. 10
   • b) Derive the expression for the probability of error of the matched filter. 10
   • a) Over a long transmission line draw the following data format for the binary sequence Unipolar NRZ ii) Polar RZ i11) Manchester Select the best and justify the
   • b) A (7, 4) cyclic code is generated using the generator polynomial g(x)
2. Q1 Generate the systematic cyclic code for the data 1100 and 1001(MSB) by long 1i) Draw the encoder and show how code words are generated for the data 1100, by tracing the path through the encoder and verify the result. 10
3. Q6 Write a short note on 20 marks
   • d) Convolution code

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