Anna University of Technology Tirunelveli 2011 B.E Computer Science and Engineering Cs 36-analog and digital communications - Question Paper

PART-A(10*2=20)

1.What is modulation index for AM?
2.Distinguish ranging from FM and PM?
3.What are the advantages of qpsk?
4.Draw the psk and fsk signals for the binary signal s(t)=1011001.
5.What is quantisation noise?
6.What are the advantages and disadvantages of digital transmission?
7.Which fault detection technique is simple and which 1 is more reliable?
8.Define data modem?
9.What are the kinds of frequency hopping?
10.Define PN sequence.

PART-B(5*16=80 marks)

11. (a) (1)Explain the frequency analysis of angle modulated waves. (10)
(2)Write short notes on bandwidth requirements for angle modulated waves (6)
or
(b)Derive the expression for the AM waves,and also plot its spectrum. (16)
12.(a) (1)Draw and discuss FSK transmitter and receiver. (10)
(2)Explain in detail about QAM. (6)
or
(b) With neat diagram,explain principle of QPSK technique. (16)
13.(a) (1) discuss in detail the delta modulation transmitter and receiver. (10)
(2)Discuss the drawbacks of delta modulation and discuss the significance of adaptive delta modulator. (6)
or
(b) Write short notes on
(1)Differential pulse modulation (10)
(2)Intersymbol Interference (6)
14.(a)Explain about Synchronous and Asynchronous modem. (16)
or
(b)Describe data communicationcodes(16)
15.(a)With the help of block diagrams and wave form,explain about DS spreadspectrum with coherent binary PSK. (16)
or
(b) (1)Explain in detail about TDMA in wireless communication techniques. (10)
(2)What are pseudo noise sequences?How are they generated? (6)

Earning:   Approval pending.