EC6651 COMMUNICATION ENGINEERING 2Marks 1. Define amplitude Modulation. 2. Define Modulation index and percent modulation for an AM wave. 3. What are the disadvantages of conventional (or) double sideband full carrier system? 4. What are the advantages of single sideband transmission? 5. State Carson’s rule. 6. Define pulse code modulation. 7. What is the purpose of the sample and hold circuit? 8. Define quantization. 9. Define slope overload. How it is reduced. 10. Define QAM. 11. What is Information Rate? 12. Mention the significance of AMI Code. 13. What are the features of Convolutional codes? 14. Mention few error control codes. 15. State the significance of Source coding. 16. Define Multiple Access. 17. What is near-far problem? 18. Mention the features of CDMA. 19. Define FDMA? 20. Give the advantages and disadvantages of TDMA.

21. Define retrograde orbit. 22. Define geosynchronous satellite. 23. What are the advantages of optical fiber communication? 24. Define a fiber optic system. 25. Define refractive index.

16marks 1. Explain a method of generation of amplitude modulated signal and sketch the time domain waveform of message, carrier and modulated signal. 2. Explain the generation of Frequency modulated signal with reactance modulation scheme with neat diagram. 3. Explain the concept of MSK and GMSK in detail. 4. Explain about Shannon–Fano coding with example. 5. Explain in detail about Code tree, State Diagram and Trellis Diagram in Convolution codes. 6. Explain about TDMA and SDMA systems. 7. Write notes on Orbits, Types of Satellite, Optical Sources and Detectors.