B.E-B.E Electronics and Communication Engineering Analog Communication (Sathyabama University, Chennai, Tamil Nadu-2011)
Monday, 19 August 2013 07:45Duraimani
(Established under section 3 of UGC Act,1956)
Course & Branch :B.E - P-ECE
Title of the Paper :Analog Communication Max. Marks:80
Sub. Code :SECX1016 (2010-2010) Time : 3 Hours
Date :18/11/2011 Session :AN
PART - A (10 x 2 = 20)
Answer ALL the Questions
1. What is the need for modulation?
2. Define SNR.
3. What is the significance of RC time constant with respect to demodulation of an AM wave?
4. Differentiate low level and high level modulation.
5. What is the need for the Pre-emphasis and De-emphasis circuits?
6. Represent an FM wave mathematically.
7. Define Multiplexing
8. Define Nyquist sampling rate.
9. What is the function of a Squelch circuit?
10. Expand CCTV.
PART – B (5 x 12 = 60)
Answer All the Questions
11. Three amplifiers have the following characteristics :
F1= 9 dB, G1= 48 dB, F2= 6 dB, G2= 35 dB, F3= 4 dB, G3= 20 Db. The amplifiers are connected in random. Determine the sequence of combination which gives the best noise figure referred to the input. Calculate the overall noise figure and equivalent noise temperature in this case.
(or)
12. Explain the various Internal sources of noise.
13. (a) Calculate the percentage power saving when a carrier and one of the sidebands are suppressed in AM wave modulated to the depth of 100%
(b) Discuss the detection scheme for AM using Square Law detector.
(or)
14. With a neat block diagram explain the working of an AM transmitter.
15. (a) Derive the expression for NBFM.
(b) Compare AM and FM modulations.
(or)
16. (a) Discuss the working of FM using Armstrong method.
(b) Explain the Foster Seeley Discriminator method of FM detection.
17. Discuss on the generation and demodulation of PPM.
(or)
18. Discuss on
(a) Quadrature Multiplexing
(b) Noise in Pulse modulation systems.
19. (a) With a neat block diagram explain the working of a super heterodyne receiver.
(b) List out the advantages of this receiver over TRF receiver.
(or)
20. (a) Discuss on Capture effect and Threshold effect. (8)
(b) Define variable selectivity and variable sensitivity. (4)
| Earning: ₹ 4.75/- |
