A 10000EE401122002 Pages: 2

Reg No.: Name:
APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY

Seventh Semester B.Tech Degree Regular and Supplementary Examination December 2021 (2015 Scheme)

Course Code: EE401
Course Name: Electronic Communication

Max. Marks: 100 Duration: 3 Hours
PARTA
Answer all questions, each carries 5 marks. Marks
1 With the help of suitable circuit arrangement and relevant characteristics (5)

explain how does a varactor diode help in the generation of FM.

Explain the operational features of super heterodyne AM receiver. (5)
Explain the constraints on the transmitter pulse power ए and minimum (5)
receivable power ‏روزم‎ for enhancing the radar range

4 With the help of block diagram and relevant characteristics explain the pulse (5)
position modulation (PPM).

Explain any one of the spread spectrum technique for CDMA implementation. (5)

6 Why do you suggest semiconductor laser as an efficient light source in an (5)
optical fibre based communication system?

7 ‘SDMA is better than TDMA for digital satellite communication’. Justify the (5)
statement with at least three valid points.

8 Identify any three features of Wi-Max and explain how does it benefit for (5)
wireless applications.

PART ‏تا‎
‎Answer any two full questions, each carries 10 marks.

9 a) A broadcast AM radio transmitter radiates 10 kW when the modulation (4)
percentage is 50. Determine the carrier power. If another sine wave is also
simultaneously transmitted with a modulation index of 0.3, determine the
overall modulation index and total transmitted power.

b) With the help of relevant characteristics and equations explain the importance (6)
of vestigial SB modulation.

10 a) With neat block diagram, explain the operation of SSB pilot carrier transmitter. (4)

b) With suitable sketches and relevant circuits explain how do you achieve S- (6)

shaped characteristics for an FM detector.

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