Anna University Exams Nov/Dec 2019 - Regulation 2017
Rejinpaul.com Anna University Semester Exam Important Questions
PART B & PART C QUESTIONS
Unit I
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EC8394 ANALOG AND DIGITAL COMMUNICATION
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Define phase and frequency modulation and derive the expression for AM and PM wave.
Compare AM, FM and PM.
With the help of neat block diagram explain about the generation of SSBSC wave and demodulation.
Explain in detail about the SSB modulation techniques.
i) Outline the generation of SSB wave using phase shift method with necessary block diagram, with the
expression for the instantaneous voltage of SSB wave. ii) Determine the peak frequency deviation and
modulation index (m) for an FM modulator with a deviation sensitivity kf = 5kHz/V and a modulating signal
v(t) = 2cos(2π2000t).
6. Discuss about the Armstrong indirect method of FM generation.
7. Derive the expression for the instantaneous voltage of SSB wave.
Unit II
1. Explain in detail the concept of PCM.
2. Explain about various operations performed in the transmitter and receiver of PCM system.
3. a) Explain the generation of PCM signal with a block diagram. b) Explain the types of data communication
codes? 1.Baudot code 2.ASCII code 3.EBCDIC code 4.Bar code
4. a) Explain the working of a two station data communication circuit with a block diagram. b) Describe the
generation and demodulation of PPM signal waveforms.
5. a) Compare the various pulse analog modulation techniques. b) Discuss the generation of PAM and its
demodulation.
Unit III
1. a) Draw the block diagram of 8-QAM Transmitter and explain its working. b) With a block diagram explain
the working of coherent binary FSK transmitter and receiver.
2. What is the significant of QAM? Explain the operation of 8 QAM Transmitter and receiver using a block
diagram and truth table.
3. Define binary FSK and explain about the generation and detection of binary FSK signals using block diagram.
4. a) Compare the various digital modulation schemes. b) Explain in detail about the operation of QPSK
Transmitter with necessary diagrams.
5. Draw the constellation diagram of QPSK modulation and explain the QPSK modulation and demodulation of
QPSK. Compare QPSK and BPSK.
6. Explain the method of generation of QAM and the demodulation of the same.
Unit IV
1. Five source messages are probable to appear as m1 =0.4, m2= 0.1, m3 = 0.2, m4 = 0.1, and m5 = 0.1, m6
=0.1. Determine the coding efficiency for 1) Shannon-Fano coding 2) Huffman coding
2. a) Derive the expression for mutual information and channel capacity. b) Discuss the types of error control
coding.
3. Draw and explain the generalized i) (n,k) cyclic encoder to implement an encoding procedure for an (n,k)
cyclic code in systematic form ii) Syndrome calculator and properties of syndrome polynomial.
4. The generator polynomial of a (7, 4) cyclic code is given by G(D)=x2+ x+ 1 . Compute all the non-systematic
codewords for the message 100.
5. Consider a systematic block code whose parity check equation are P1=m1+m2+m4 P2=m1+m3+m4
P3=m1+m2+m3 P4=m2+m3+m4 Where Mi is the message digits and Pi are the parity digits? i) Find the
generator matrix and the parity check matrix for this code. ii) How many errors can be detected and
corrected? i) If the received code word is 10101010, find the syndrome
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6. A source generates five messages m0, m1, m2, m3, m4 with probabilities 0.55, 0.15, 0.15, 0.10, 0.05
respectively. The successive message emitted by the source are statistically independent. Determine code
words for the messages and efficiency using shannon Fano algorithm.
7. Explain source coding theorem. Consider five messages So, S1, S2, S3, S4 given by the probabilities ½, ¼, 1/8,
1/16, 1/16. Use Shannon Fano algorithm to develop an efficient code.
8. A) Write short notes on linear block codes. B) Devise a single-bit error correction code for 8-bit data and
illustrate with an example.
Unit V
1. Discuss in detail about the architecture of GSM with necessary diagram.
2. Describe the concept of frequency reuse, channel assignment and hand-off in a cellular system.
3. Explain in detail about the function of each layer in Bluetooth system (Bluetooth technology).
4. Explain the principle of working of satellite communication with block diagram.
5. Compare different multiple access techniques with its advantages and disadvantages.
6. Explain in detail about the techniques of CDMA with its features. Write down the problems faced by CDMA
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