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- COMMUNICATION SYSTEM ENGINEERING - CSE
- 2017
- PYQ
**Biju Patnaik University of Technology BPUT - BPUT**- Electronics and Instrumentation Engineering
- B.Tech
**874 Views**- 11 Offline Downloads
- Uploaded 1 year ago

Registration no: Total Number of Pages: 02 B.Tech PCEI4301 5th Semester Back Examination 2017-18 COMMUNICATION SYSTEM ENGINEERING BRANCH:AEIE, BIOMED, EIE Time: 3 Hours Max Marks: 70 Q.CODE: B242 Answer Question No.1 which is compulsory and any five from the rest. The figures in the right hand margin indicate marks. Q1 a) b) c) d) e) f) g) h) i) j) Answer the following questions: Define the transmission efficiency of AM signal. Distinguish between linear and non-linear modulator with example. what is meant by indirect FM generation? What is the bandwidth required for an FM wave in which the modulating frequency signal is 2 KHz and the maximum frequency deviation is 12 KHz? What is aliasing?How to avoid aliasing effect? For the signal m (t) = 3 cos 500 *3.14t + 4 sin 1000*3.14 t , Determine the Nyquist sampling rate. For an energy signal x(t), define the auto-correlation function. Determine the Fourier transform of the following signals. (i) X(t)= t cos2πf0t (ii) X(t)= t e−αt cos(βt),α being positive. Use the convolution theorem to show that sinc(t)*sinc(t) =sinc(t) Define eye pattern. (2 x 10) Q2 a) Explain the Functional block diagram of a communication system in detail. b) Explain the digital communication system and distinguish it from Electrical system. (5) (5) Q3 a) Alineartime-invariantsystemwithimpulseresponse ( ) = ( )is driven by the input ( ) = ( ).It is assumed that , > 0. Using frequency domainanalysis,ﬁndtheoutputofthesystem.Istheoutputpowertypeorenergy-type? Find its power or energy. b) Determine the Fourier series expansion of the following signals. i. x(t)= cos t+ cos 2.5t ii. ( )= − ( − ) (5) Q4 a) Discusses the method of generating a single side band signal using balanced modulators and phase shifters. b) Discuss about the VSB modulation system and write its application (5) (5) (5)

Q5 a) The modulated signal is given as S(t)= 10 cos (ωct+5 sin 6000t+10sin 4000πt). The carrier frequency is ωc= 2π×106 radian. Find power of the modulated signal, frequency deviation, modulation index, phase deviation, and the band width of S(t). (5) b) An angle-modulated signal is given as u(t) =100cos[2000πt +φ(t)] where (a) φ(t) = 5sin20πt, and (b) φ(t) = 5cos20πt. Determine and sketch the amplitude and phase spectra for (a) and (b), and compare the results. (5) Q6 a) How can you generate an FM from PM and PM from FM? b) Describe the operation of Differential Pulse Code Modulation system with a relevant diagram. (5) (5) Q7 Draw the block diagram and describe the operation of a delta modulator. What are its advantages and disadvantages compared to a PCM system? An 8 bit PCM system is employed in a telephone network having an analogue bandwidth of 4000Hz. Determine the sampling rate, bit rate & the require bandwidth. (10) Q8 Write short answer on any TWO: Time Division Multiplexing of PCM signals Noise in Delta Modulation Amplitude Modulation power distribution. Envelop Detection. a) b) c) d) (5 x 2)

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