Question Paper: Principles of Analog & Digital Comm. : Question Paper May 2014 - Information Technology (Semester 3) | Mumbai University (MU)
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## Principles of Analog & Digital Comm. - May 2014

### Information Technology (Semester 3)

TOTAL MARKS: 80
TOTAL TIME: 3 HOURS
(1) Question 1 is compulsory.
(2) Attempt any three from the remaining questions.
(3) Assume data if required.
(4) Figures to the right indicate full marks.
1 (a) Explain friiss transmission formula.(5 marks) 1 (b) What are the energy signal and power signals.(5 marks) 1 (c) Explain Ask system.(5 marks) 1 (d) Compare pcm and Delta modulation.(5 marks) 2 (a) Explain the operating principle, working of transmitter and receiver of BPSK system.(10 marks) 2 (b) An amplitude modulated ware form has a form
Xc(t)=10 (1+0.6 Cos2000?t+0.4 Cos400?t)Cos2000?t)
(i) Sketch the amplitude spectrum of Xc(t)
(ii) Find the power content of each spectral component including currier.
(iii) Find total power and sideband power.
(iv) What is modulation index.
(10 marks)
3 (a) What is meant by sensitivity of a radio receiver and How it is improved.(10 marks) 3 (b) Find the mathematical expression of FM signal.(10 marks) 4 (a) State and prove the sampling theorem for low pass and limited dignal. Explain aliasing error.(10 marks) 4 (b) Explain the working of foster seeley discriminator with neat ckt diagram and phasor diagram.(10 marks) 5 (a) What is meant by sensitivity of a radio receiver and How it is improved.(10 marks) 5 (b) What are the advantage of QPSK system.(5 marks) 5 (c) Compare analog and digital communication system.(5 marks) 6 (a) What are advantage and dis-advantage of digital communication also draw block diagram of pcm and explain it.(10 marks) 6 (b) Explain the following in relation of radio receiver
(i) Selectivity
(ii) Sensitivity
(iii) Double spotting.
(10 marks)