6th Semester Electronic and Communication Engineering (2012-June) Question Papers

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Max - Marks:100

Note: Answer FIVE full questions, selectingat least TWO questions from each part.

PART-AWith a neat block diagram, explain the operations of digital communication system. Explainthe functioning of each block. (06 Marks)A signal g(t) = l0 cos (20nt) cos (200nt) is sampled at the rate of250 samples/sec.i) Sketch the spectrum ofthe sampled signalii) Specify the cut-off ideal reconstruction filter so as to recover g(t) from g,(t)iii) Specify the Nyquist rate for the signal g(t). (08 Marks)What is flat-top sampling? Derive an expression for the flat-top sampled signal. (06 Marks)

Show that the signal to quantization noise power ratio of a uniform quantizer is

p [ :p 'l-.-

-,,1,12'". {08Marks)oa Lc;_ lFor a binary PCM signal, determine L if the compression parameter p = 100 and theminimum [SNR]0. ae = 45 dB. Determine the [SNR]6. dB with this value of L. (06 Marks)With a neat block diagram and waveforrn, explain time division multiplexing. (06 Marks)

With a neat block diagram, explain delta modulator transmitter and receiveq and alsoexplain the errors in delta modulation. (08 Marks)Obtain the power spectral density of NRZ polar format and draw normalized diagram.


Derive the Nyquist criterion for distortionless baseband binary transmission. (08 Marks)What is eye pattem? Explain in detail. (06 Marks)With a neat filter structure, explain the concept ofadaptive equalization process. (06 Marks)

Sixth Semester B.E. Degree Examination, Jlune 2012

Digital Gommunication

Compare DM with DPCM.

PART-BList the important requirements of passband transmission scheme.

pulse.What are the advantages of MSK over QPSK?

Estimate the power spectral density of a BPSK signal from Fourier transform of basic NRZ

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Explain geometric interpretation of signals.

06EC61

(08 Marks)Three signals Sr(t), S2(t) and S:(0 are shown in Fig.Q6(b). Apply Gram-Schmidr procedureto obtain an orthonormal basis for the signals. Express signals S1(t), Sdt) and S3(t) in termsoforthonormal basis functions. Also give the signal constellation diagram. (12 Marks)

Fig.Q6(b)

7 a. Show that the probability ofbit error of a matched filter receiver is given by:,t.

P. = I erfc. ilL . (12 Marks)" 2 llN,b. Draw and explain the block diagram of conelation receiver. (0E Ma*s)

8 a. What is spread spectrum technique? Explain the working of direct sequence spread spectrumtransmitter and receiver.

b. Explain the properties ofPN sequence.

c. Compare slow and fast frequency Hopping.

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Sixth Semester B.E. Degree Examination, June 2Ol2Microprocessors

Time: 3 hrs. Max. Marks:100*

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PART - AI a. What is a microprocessor? What are the components required to build a minimum

microcompuigr system? Explain with a neat diagram. (06 Marks)

b. What are the roles of each element in the BIU of 8086 CPU? Explain with a neat diagram.How is the 20-bit physical address for memory generated? Explain with an example.

( l0 Marks)

c. What is the minimum size and maximum size of an instruction in 8086? Explain withexamples. (04 Marks)

2 a. Explain the importance of each field in Byte-l and Byte-2 of the 8086 instruction template.If the 6-bit op-code for ADD instruction is "000000" then formulate the op{ode/s for"ADD AX, CX" insfiuction. (07 Marks)

b. What are the pseudo codes? Explain the following directives with examples:i) ENDP ii) EXTRN iii) GLOBAL iv) PROC. (07 Marks)

c. Write the single instruction equivalent for the following program segments if available andjustify your answer; assume that these program segments are stafting fiom memory locationFFFF0h and 8086 is resetjust before execution.

i)FFFFo: MovCL, lOh iitFFFFO: I-o^l,tI: A\_,.-OxcHG AX.BX MOVBX. AXiSRoR AX.CL ADDAx.BFi7

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T:-\3 a. What is a procedure? What are its advantages? V

b. Write a 8086 procedure to conven a packed BCD number in AL to(0,6 Marks)

c. How do you invoke near procedures and far procedures in 8086? What are the methodsavailable for palameter passing in procedures? (06 Marks)

d. What makes a MACRO facility to be prefered over a procedure in a program development?(04 Marks)

a. What is the response of 8086 pp when interrupted? Explain clearly. (0,6 Marks)

b. Explain the interrupt system of 8086 CPU with allthe sources of interrupts. (08 Marks)

c. How many string instructions are available in 8086 instruction set? Explain briefly.(06 Marks)

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PART-B

Why interfacing is required? Explain.

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What do you mean by key-debouncing? Explain briefly hardware debouncing and softwaredebouncing methods. (05 Marks.)

c. lnterface a 4x4 keypad to 8086 cPU and write a program to identifu any key pressed. writenecessary comments.

6 a. What are the functions of the following 8087 instructions? Explain.i) FBSTP TAX ii ) FSUBR Dr, Sr iii) FXAM iv) FLDL2EInterface 8087 NDP to 8086 CPU; indicate all critical signal connections.

Write a program using 8086 instruction to check whether pCI bususing BIOS.

For an USB in personal compuEr give:

b. With a neat block diagram, explain the Pentium architecture and features.

write a program to compute roots of a quadratic equation using 8087 instructions. (07 Marks)

What is maximum mode of operation for 8086 CpU means? Show all necessaryarrangements for 8086 maximum mode. (07 Marks)

i) Pin configuration ii) Two cRC polynomials iii) Token packet & data packet. (07 Marks)

8 a. Using a block diagram, briefly indicate different signal groups on 80386 processor.(10 Marks)

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Sixth Semester B.E. Degree Examination, Jrone 2Ol2Antenna and Propagation

Time: 3 hrs. Max- Marks:1OONote: Answer FIVE full questions, selecting

at least TWO questions from each part.

PART - AI a. State and explain: Aperature efficiency, effective height and bandwidth of an antenna.(09 Marks)

b. Show that the directivity of an antenna is the ratio of the area of a sphere to the beam area.

c. Derive Friis transmission formula. l8:l[:il]2 a. The radial component of the radiated power density of an infinitesimal linear dipole of

length / << ). is given by a'A'f in':e where A. = peak value of the power density,

r& = radial unit vector. Find the directivity of the antenna. (06 Marks)

b. Prove that directivity for a source with unidirectional pattern of Um Cosn0 (where n is anynumber) can be expressed as D = 2(n + I ). (06 Marks)

c. Obtain the field pattern for two point sources situated symmetrically with respect to theorigin. Two sources are feed with equal amplitude and equal phase signals. Assume:Distance between two sources = 1"/2- (08 Marks)

3 a. Derive an expression for electric field component of a linear antenna of length X/2long.(12 Marks)

b Derive the expression for radiation resistance of a short dipole with uniform cur..nlor ru.u*)

Write notes on:Pattem multiplication.Power distribution in broad side array.Radiation pattem.

PART - B5 a. Derive the expression for E field component of a small circular loop antenna of radius 'a',

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carrying cument I.b. State and illustrate Babinets principle.

Write short notes on:Lens antenna.Log-periodic antenna.Antennas for ground penetrating radar.

What is meant by diffraction of radio waves? Define knife edgi'dilTiaction gain.Describe ground wave propagation.Obtain the expression for line of sight distance between the transmit and receiver antennas.

(06 Marks)

Discuss the reflection mechanism where by electromagnetic waves are bent back by a layerofthe ionosphere. Include in your discussing a description of the virtual height of a layer.

(12 Marks)Describe briefly the strata of the ionosphere and their effects on sky wave propagation.

(08 Marks)

tUSN 068C662


(04 Marks)



Sixth Semester B.E. Degree Examination, Jrune 2Ol2Satellite Gommunication

Time: 3 hrs. Max. Marks: 100

Notet Answer FIVE full questions, selectingat least TWO questions from each part.

PART-AI a. List the fiequency-band designations. Which are in common use for satellite services?Ya9

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c. State and explain the Kepler's laws of planetary motion with neat diagrams and necessary

equations. (10 Marks)

2 a. Determine the limits of visibility for an earth-station situated at mean sea level at Iatitude

48.42"N and longitude 89.26"W. Assume a minimum angle of elevation of 5". (06 Marks)b. Explain the Keplerian element set with their meanings with resp,eet4e sa

[. What is INTELSAT? How it covers the 'International traffic'?

c. What are antenna look angles? How these are determined?d. Determine which of the followings years are leap years:

i) 1987 ii) 1988 iii) 2000 iv) 2100.

Explain atmospheric and ionospheric losses for satellites.Briefl y explain uplink-and-downlink rain-fade margin.

[B]rn = 75.56.c. Explain the 'frame and burst formats' for a TDMA system.

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c. Calculate 'horizontal, vertical and circular' polarizations for a frequency of l2 GHz, the rarn

attenuation is exceeded for 0.019o of the time in any year, for a point rain rate of l0 mm/h.

The earth station attitude is 600 meter, and the antenna elevation angle is 50'. The rainheight is 03 km and an = 0.0188; br, = 1.217: a, = 0.168; b, = 1.2.

Note: All lengths and heights are in kms, and rain-rate is in mm/hour. (10 Marks)

4 a. What is a satellite transponder? With a neat diagram explain the overall frequencyarlangement oftypical C-band communication satellite. (06 Marks)

b. A satellite downlink at l2 GHz operates with a transit power of6 watts and on antenna-gain

of 48.2 dB. Calculate EIRP in dBW. (04 Marks)

c. What is meant by satellite attitude? Briefly describe three-axis method of satellitesatelelization. (10 Marks)

PART - B5 a. With a neat diagram, explain the outdoor-and indoor units of a receive-only home TV

system. (10 Marks)

b. What is meant by pre-assigned FDMA? With a neat diagram, explain single channel per

carrier' (10 Marks)

6 a. The carrier-to-interference ratio at the ground receiving antenna is 23.3 dB. For the uplink

lclll ratio is 27.53 dB. Find the overall ratio [C/I]anr for (I/C)u = 0.001766 and

(I/C)p = 9.994436. (06 Marks)

b. Calculate the fCA{lo for IEIRP]o = 27, lcff)D = 30, [LOSSES]o = 196, tkl = -228.6 and

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Explain:i) Transpondercapacityii) Frequency and polarization.iii) Bit-rate for digital TV.Explain in detail the satellite mobile services.

Write short notes on any three choosing any one from c. and d.Geo- stationary orbit.VSAT and its applications.GPS and its uses.

Radarsat.

06EC662

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(20 Marks)

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USN

Time: 3 hrs.

06EC661

Max. Marks: 100

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Sixth Semester B.E. Degree Examination, Jrune 2Ol2

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PART - A

Explain enumeration data types with examples.What do mean by dynamic initialization of a variable? What is thebetween static and dynamic memory allocation.Write a note on #define directive and const modifier.Explain the difference between the four objects defined below:i) int ival = 1024

ii) int *pi2 = new int (1024)iii) 1n1 *pi = &ivaliv) int *pi3 = new int [024].

a. What is pointer? Explain the advantages of a pointer. Indicate theaddress operator and indirection operator.

b. What are the basic operations performed on string. Write a programIength of the string using string type.

c. Give lhe output of the following:void main( ){

int i=4, j = -1, k =0, w, x, y, z:

w=ill: llr;x=i&&j&&k;y=illjaahz=i&&j llk;

cout <<w<<x<<y<<z;)

b. Write a recursive function to find factorial of n numbers.c. What is a function? Mention the advantages of using functions.

a. What are bitwise operators? Explain the left shift and right shift operations with examples.(04 Marks)

b. Explain the various looping constrants available in C++ with their syntax and examples.(06 Marks)

c. Explain with the syntax the components of the switch statements. Write a program in C++ tocount the number of vowels in a given string. (10 Marks.l

a. Explain the callof each.

by value and call by reference parameter passing method with an example

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06EC661

PART-B

What is an exception? With the help of example explain how the try block and catch blockworks. (10 Marks)

Write a C++ program to illustrate the process of catching all uncaught exceptions through in

5a.

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a try block.

Explain parameterized constructors. Develop a C++constructor.Explain the following features of OOP's:i) Classesii) Objectsiii) Polymorphismiv) Inheritancev) Encapsulation.

(10 Marks)

program to implement parameterized(10 Marks)

(10 Marks)

(I0 Marks)


7 a. What is an operator over loading? Write a C++ program to add 2 complex numbers by overloading the operator '+'. (10 Marks)

b. Explain how an array of objects can be created and members of the objects are accessed.

Give example.

8 a. Explain single and multilevel inheritance with examples.

b. Briefly explain public, private, protected inheritance.

c. Write a note on base class and derived class.

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6th Semester Electronic and Communication Engineering (2012-June) Question Papers

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