Page 1 of 2

Sreenidhi Institute of Science & Technology (An Autonomous Institution)

Code No: 101EC11/111EC11

B. TECH. II – Year II – Semester Examinations, January, 2014 (Supplementary) ANALOG COMMUNICATIONS (ECE)

Time: 3 Hours Max. Marks : 70

Note : No additional answer sheets will be provided.

Part-A (Objective Type) Max.Marks:20

ANSWER ALL QUESTIONS.

1. Define Angle Modulation.

2. List out - receiver characteristics.

3. Write the necessity of AGC.

4. What are the merits of SSB - SC signal.

5. List out the band widths of AM, DSBSC and SSB.

6. How do you classify transmitters?

7. What is Nyquist rate?

8. Compare PAM and PWM signals.

9. What is transmission band width of FM signal.

10. Explain threshold effects in angle modulated system.

Part – B Max. Marks: 50

ANSWER ANY FIVE QUESTIONS. EACH QUESTION CARRIES 10 MARKS. 1. a) Explain how AM is generated using switching modulator. Derive the

relevant expression. [5+5]

b) Explain how AM is detected using square law detector.

2. a) Derive the equation for wide band FM wave and draw its spectrum.

b) What is zero crossing detector? Explain how it can be used as FM

demodulator. [5+5]

3. a) Compare narrow band FM and wide band FM. [5+5]

b) Explain how amplitude limiting is achieved in FM ratio detector.

A 10

Page 2 of 2

4. Prove that the figure of merit of DSB - SC receiver is unity.

5. a) Draw the block diagram of a FM transmitter and explain each stage. [5+5]

b) What are the requirements of radio transmitters.

6. a) List out the advantages and disadvantages of TRF receiver. [5+5]

b) List and discuss the factors influencing the choice of the intermediate

frequency for a radio receiver.

7. a) Present the differences between FM and AM receivers. [4+6]

b) Explain clearly about the super heterodyne principle.

8. Write a brief note on

i) sampling theorem ii) PPM generation and demodulation.

-- 00 -- 00 --