QUESTION BANK (POC:EEC-502) Section A 1.What is the need of modulation? Write a short note. 2.Explain one of the following a.Diagonal clippingb.Phase discriminator method for SSB-SC.3.Explain the following:Base band signalBand-pass modulationDemodulation of FM using PLL Difference between analog and digital communication4.State the sampling theorem and explain. How will you recover the signal from its samples?5.What is vestigial sideband and how it is different from SSB transmission?6.Why over modulation is undesirable for amplitude modulation system?7.Compare the feature of AM/FM and FM signal.8.What is the function of band pass limiter?9.Draw the block diagram of phase shift method for generating the SSB signal and explain its working.10. Explain the concept of heterodyning. What are the advantages of heterodyning?11. DiscusshowtheVSBmodulationisusedincommercialTVsignals.Discussitsmeritsand demerits. 12. Explain the working of square law modulator for AM wave.13. Explain the different type of Noise in detail.14. Distinguish between Narrowband FM and Wideband FM with their basic equation.15. Drivetheexpressionforsignaltoquantizationnoisepowerratiofordeltamodulation. Assume that no slope overload distortion exists.16. For a full scale sinusoidal modulating signal with amplitude, prove that the output signal to quantizationnoiseratioforPCMsystemis(SNR)o=(3L2/2)whereListhenumberof quantizing levels.17. Compared the Line coding for power spectral density of unipolar, bipolar and polar signaling.Section B18. Prove that for VSB-SC filter characteristic condition will be , where is the impulse response of VSB SC filter.19. Explainchoppertype(switching)modulatorforDSB-SCsignalwithmathematical explanation. 20. WhatistherelationbetweenPM&FM.Givetheblockdiagramforthegenerationof Narrowband FM and PM generation?21. Prove that the balanced modulator produce an output consisting of sidebands only with the carrier removed. What the application can this circuit have?22. What is the effect of modulation index in the spectrum of modulation index? Hence explain the effect of Carsons rule in B.W. of FM signal.23. Explain the demodulation technique of pulse width modulation. 24. Compare FDM and TDM technique.25. Explain the Armstrong method for the generation of Wideband FM.26. Drive the expression for single tone modulated wave.27. Definethesamplingprocessandexplainitsnecessityincommunicationsystem.Also compare PAM PPM and PWM system.28. GivetheworkingofdemodulationofPWMandPPMwiththehelpofneatandclean waveform diagram and block diagram. 29. Write a note on TDM PCM hierarch system from T1 to T4.30. For a binary sequence 0010110110101 construct RZ, NRZ, AMI and Manchester format.31. Write a short note on internal noise and External Noise.32. Explain Spike generation and threshold effect in FM. What is capture effect? 33. Write a short note onLinear and nonlinear modulationDemodulation of FMSection C33. Prove that if every frequency component of a signal f(t) is shifted by ,the resultant signal is theHilbert transform of f(t) which is given by. Give all properties ofHilbert transform.34. What is slope overload? What is granular noise? 35. Prove the condition of time constant RC for Linear Diode Detector.36. Explain narrowband noise in communication system.37. For RC low pass filter find out the average noise power.38. Evaluate the output signal to noise ratio for AM.39. Evaluate the output signal to noise ratio for FM.40. What is narrowband noise and how it is mathematically represented?41. Write a short note on amplitude modulation system and angle modulation system.42. What is digital phase locked loop?43. What do you mean by figure of merit? Why it is necessary to employ pre-emphasis and de-emphasis in the FM system?44. GiventhemethodforgenerationofAMDSBSCsignal.Howwillyoudemodulatesuch signals? Give suitable functional diagram with necessary mathematical analysis. 45. Prove that for the FM demodulation the SNR decreases as the maximum frequency content of message signal increases. 46. Prove that figure of merit for AM is constant. 47. Obtain figure of merit for the following methods of AM Demodulationa)AM b)DSB-SC c)SSB-SCd)Envelope demodulatione)Square law demodulation48.Solved numerical from Taube and Schilling book, Principles of Communication.