SRM University 2007 B.Tech Electronics and Communications Engineering BANK : Communication Engineering - Question Paper

S.R.M. Institute of Science & Technology
School of Electronics & Communication Engineering

ques. BANK
Subject Code : EC314
Subject Name : Communication Engineering
Year & Sem : III Year , sixth Sem (EEE)

UNIT I
PART - A
1. Define Modulation.
2. Write the need for Modulation.
3. Define Amplitude Modulation & draw its Spectrum.
4. Define Modulation Index of AM.
5. What are the various degrees of Modulation?
6. What is the power efficiency or power saving in AM, SSB, DSB-SC?
7. Write the advantages of SSB.
8. Draw the circuit diagram of Balanced Modulator for generating AM with carrier.
9. Give 2 methods of generating DSB-SC.
10. Compare DSB-SC & SSB.
11. State the demerits of Square-law Modulator.
12. Give the advantages of Suppressing a carrier during transmission.
13. Compare linear & non-linear modulator.
14. Compare various AM methods.
15. Mention a few applications of SSB.
16. Give the bandwidth needed to transmit AM, DSB-SC & SSB.
17. What is VSB?
18. Draw the frequency Spectrum of AM,SSB & DSB-Sc.
19. Write the expression for total power of AM in terms of carrier power Pc ?
20. Define critical Modulation.
21. A transmitter supplies 8KW to the antenna when unmodulated. Determine the total power radiated when modulated to 30%.

22. A 1MHz carrier is amplitude modulated by 400Hz,modulating signal to a depth of 50%.The modulated carrier power is 1KW.Calculate the power of unmodulated signal.

23. A sinusoidal Carrier voltage of frequency 1MHz & amplitude 100 volts is modulated by sinusoidal voltage of frequency 5KHz producing 50% modulation. compute the frequency & amplitude of USB & LSB.

24. A 400W carrier is modulated to a depth of 70%. obtain the total power transmitted for the subsequent forms of AM signal, AM, DSB-SC, SSB.
25. Define Thermal noise & Shot noise.
26. What are the various kinds of noise?

PART – B

1. Define Amplitude modulation & derive an expression for Amplitude modulated wave and its power relation .
2. Explain Balanced Modulator technique for the generation of DSB-SC wave.
3. Explain Square legal regulations method for the generation of amplitude modulation.
4. Explain Phase Discrimination & frequency discrimination method of generation of SSB.
5. Explain the method of generation of VSB.
6. Explain Ring modulator in detail.
7. Explain any 1 of the linear modulator for generating AM wave.
8. Explain any 1 non-linear modulator for generating AM wave
9. Explain about internal & external noise.
10. Compare various methods of AM.
UNIT II
PART – A

1. Define Demodulation.
2. Give the difference ranging from low level & high level AM transmitter.
3. Define Envelope detection.
4. Draw the circuit diagram of Square legal regulations detector.
5. Define diagonal clipping.
6. What is the function of master oscillator?

Earning:   Approval pending.