8/12/2019 EC2311 CE - April 2011

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Reg. No. :

B.E./ B.Tech. DEGREE EXAMINATION, APRIL/ MAY 2011

Fifth Semester

Electrical and Electronics Engineering

EC 2311 COMMUNICATION ENGINEERING

(Regulation 2008)

Time : Three hours Maximum : 100 marks

Answer ALL questions

PART A (10 2 = 20 marks)

1. Write down the basic principle used in super heterodyne receivers?2. Draw the frequency spectrum of the amplitude modulated signal

tttts355 102cos5102cos3102cos5)( += .

3. What is meant by the term aliasing?4. How is PPM obtained from PWM?5. Define entropy.6. Draw the NRZ signaling format of given binary sequence 1101001.7. Briefly explain the multiple access technique used in satellite link.8. Mention the applications of multiple access technique in wired

communication.

9. Write down the uplink and downlink frequencies used in satellitecommunication systems.

10. Mention the types of sources and detectors used in optical fibercommunication systems.

PART B (5 16 = 80 marks)

11. (a) (i) Explain a method of generation of an amplitude modulatedsignal and sketch the time domain waveform of message, carrierand modulated signals. (10)

(ii) Derive the power relationship of Amplitude modulated signal. (6)

Or

(b) (i) Explain the generation of frequency modulated signal usingreactance modulation scheme with neat diagram. (10)

(ii) Describe the relationship between FM and PM. (6)

Question Paper Code :11293

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8/12/2019 EC2311 CE - April 2011

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12. (a) (i) With neat sketch Explain the generation of Delta Modulatedsignal and derive the expression for SNR. (12)

(ii) State the drawbacks of DM and suggest a method to overcomeit. (4)

Or

(b) (i) Explain the QPSK modulation schemes with its constellationdiagram. (10)

(ii) Briefly describe the concept of QAM and draw the constellationdiagram of 16 QAM. (6)

13. (a) (i) Write in detail the procedure of Shannon- Fano coding scheme. (8)(ii) Apply the above method to a source which generates symbols

4321 ,,, xxxx with the probabilities 1/8, 1/2, 1/4 and 1/8

respectively and determine the coding efficiency. (8)

Or

(b) (i) Compare the coding schemes HDBP and MBnB codes in terms ofbandwidth, SNR and transmission efficiency. (10)

(ii) Describe Bandwidth SNR trade off. (6)

14. (a) With neat block diagram explain the Frequency Division MultipleAccess Technique. Discuss its application in communication.

Or

(b) (i) Explain the application of CDMA in wireless communication. (10)

(ii) Compare the performance of CDMA with FDMA and TDMA. (6)

15. (a) (i) Draw the block diagram of satellite link and explain. (10)(ii) Write a brief note on INSAT. (6)

Or

(b) (i) Describe the principle of operation of power line carriercommunication. (8)

(ii) Draw the block diagram of optical fiber communication link andexplain. (8)

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