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

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  • 1. USN 06E,C61 Sixth Semester B.E. Degree Examination, Jlune 2012 Digital Gommunication Time: 3 hrs. Max - Marks:100 Note: Answer FIVE full questions, selecting at least TWO questions from each part. PART-A I a. With a neat block diagram, explain the operations of digital communication system. Explain the functioning of each block. (06 Marks) b. A signal g(t) = l0 cos (20nt) cos (200nt) is sampled at the rate of250 samples/sec.EA i) Sketch the spectrum ofthe sampled signal ii) 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) c. What is flat-top sampling? Derive an expression for the flat-top sampled signal. (06 Marks) 2a. Show that the signal to quantization noise power ratio of a uniform quantizer is p [ :p l-.- {08Marks) -,,1,12".l oa Lc;_ h. For a binary PCM signal, determine L if the compression parameter p = 100 and the minimum [SNR]0. ae = 45 dB. Determine the [SNR]6. dB with this value of L. (06 Marks).s.l c. With a neat block diagram and waveforrn, explain time division multiplexing. (06 Marks) 3a. With a neat block diagram, explain delta modulator transmitter and receiveq and alsod,- modulation. explain the errors in delta (08 Marks)6cd b. Obtain the power spectral density of NRZ polar format and draw normalized diagram. (08 Marks) c. Compare DM with DPCM. (04 Marks)!6 4a. Derive the Nyquist criterion for distortionless baseband binary transmission. (08 Marks).E 9p b. What is eye pattem? Explain in detail. (06 Marks) c. With a neat filter structure, explain the concept ofadaptive equalization process. (06 Marks) PART-B-l .i 5a. List the important requirements of passband transmission scheme. (04 Marks)z b. Estimate the power spectral density of a BPSK signal from Fourier transform of basic NRZ pulse. (12 Marks) C. What are the advantages of MSK over QPSK? (04 Marks) l of 2
  • 2. - 06EC61 6a. Explain geometric interpretation of signals. (08 Marks) b. Three signals Sr(t), S2(t) and S:(0 are shown in Fig.Q6(b). Apply Gram-Schmidr procedure to obtain an orthonormal basis for the signals. Express signals S1(t), Sdt) and S3(t) in terms oforthonormal basis functions. Also give the signal constellation diagram. (12 Marks) Srl4) s*t*) Fig.Q6(b) 7 a. Show that the probability ofbit error of a matched filter receiver is given by: ,t. P. = I erfc. " 2 ilL . (12 Marks) 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 spectrum transmitter and receiver. (10 Marks) b. Explain the properties ofPN sequence. (06 Marks) c. Compare slow and fast frequency Hopping. (M Marks) {. ,.! 2of2
  • 3. IIt 1",vaI USN 06E.C62 Sixth Semester B.E. Degree Examination, June 2Ol2 Microprocessors Time: 3 hrs. Max. Marks:100 * "r., " ", ", {{: #::,1: r:i::: ::,:;fr1,,. ai = PART - A 9 I a. What is a microprocessor? What are the components required to build a minimum o. microcompuigr system? Explain with a neat diagram. (06 Marks) i 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. L ( l0 Marks) f-i_ !a! c. What is the minimum size and maximum size of an instruction in 8086? Explain with examples. (04 Marks) *- ll 2 a. Explain the importance of each field in Byte-l and Byte-2 of the 8086 instruction template. Y., If the 6-bit op-code for ADD instruction is "000000" then formulate the op{ode/s for ()tr "ADD AX, CX" insfiuction. (07 Marks) 3e b. What are the pseudo codes? Explain the following directives with examples: i) ENDP ii) EXTRN iii) GLOBAL iv) PROC. (07 Marks) 9.s c. Write the single instruction equivalent for the following program segments if available and .Jo justify your answer; assume that these program segments are stafting fiom memory location boc FFFF0h and 8086 is resetjust before execution. €E i)FFFFo: MovCL, lOh iitFFFFO: I-o^l,tI: A_,.-O AX.BX xcHG MOVBX. AXiS -.4 AX.CL RoR ADDAx.BFi7 J,- XCHGAX,BX XCHGAX,EXT Mad<s) 7v =ia T:- 3 a. What is a procedure? What are its advantages? l): ,;6 V Marks) ,t! b. Write a 8086 procedure to conven a packed BCD number in AL to in AX. !o (0,6 Marks) b!o c. How do you invoke near procedures and far procedures in 8086? What are the methods available for palameter passing in procedures? (06 Marks) != 9- d. What makes a MACRO facility to be prefered over a procedure in a program development? (04 Marks) oi -i ci a. What is the response of 8086 pp when interrupted? Explain clearly. (0,6 Marks) z b. Explain the interrupt system of 8086 CPU with allthe sources of interrupts. (08 Marks) s c. How many string instructions are available in 8086 instruction set? Explain briefly. E (06 Marks) 1of 2
  • 4. o6EC62 PART-B5a. Why interfacing is required? Explain. (03 Marks) b. What do you mean by key-debouncing? Explain briefly hardware debouncing and software debouncing methods. (05 Marks.) c. lnterface a 4x4 keypad to 8086 cPU and write a program to identifu any key pressed. write necessary comments. (12 Ma*s)6 a. What are the functions of the following 8087 instructions? Explain. i) FBSTP TAX ii ) FSUBR Dr, Sr iii) FXAM iv) FLDL2E (06 Marks) b. Interface 8087 NDP to 8086 CPU; indicate all critical signal connections. (O7 Marks) c. write a program to compute roots of a quadratic equation using 8087 instructions. (07 Marks)ta- What is maximum mode of operation for 8086 CpU means? Show all necessary arrangements for 8086 maximum mode. (07 Marks) b. Write a program using 8086 instruction to check whether pCI bus extension is available using BIOS. (06 Marks) c. For an USB in personal compuEr give: 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) b. With a neat block diagram, explain the Pentium architecture and features. (10 Marks) 2of2
  • 5. 068C64IU USN Sixth Semester B.E. Degree Examination, Jrone 2Ol2I Antenna and Propagation I l Time: 3 hrs. Max- Marks:1OOI Note: Answer FIVE full questions, selecting at least TWO questions from each part. PART - A .9 I a. State and explain: Aperature efficiency, effective height and bandwidth of an antenna. (09 Marks) g 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] . .:r 2 a. The radial component of the radiated power density of an infinitesimal linear dipole of length / << ). is given by aAf 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 any number) can be expressed as D = 2(n + I ). (06 Marks) E -*. E() c. Obtain the field pattern for two point sources situated symmetrically with respect to the origin. 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: i-- a. Pattem multiplication. (07 Marks) =. b. Power distribution in broad side array. (06 Marks) C. Radiation pattem. (07 Marks) o.. PART - B ".; 5 a. Derive the expression for E field component of a small circular loop antenna of radius a, 3: carrying cument I. (12 Marks) b. State and illustrate Babinets principle. (08 Marks) 6 Write short notes on: a. Lens antenna. (07 Marks) =v b. Log-periodic antenna. (07 Marks) 3! c. Antennas for ground penetrating radar. (06 Marks) 7a. What is meant by diffraction of radio waves? Define knife edgidilTiaction gain. (07 Marks) b. Describe ground wave propagation. (07 Marks) o Obtain the expression for line of sight distance between the transmit and receiver antennas. z c. (06 Marks) c E 8a. Discuss the reflection mechanism where by electromagnetic waves are bent back by a layer ofthe ionosphere. Include in your discussing a description of the virtual height of a layer. (12 Marks) b. Describe briefly the strata of the ionosphere and their effects on sky wave propagation. (08 Marks)
  • 6. t USN 068C662 Sixth Semester B.E. Degree Examination, Jrune 2Ol2 Satellite Gommunication Time: 3 hrs. Max. Marks: 100 Notet Answer FIVE full questions, selecting at least TWO questions from each part. PART-A Ya9 o,a I a. List the fiequency-band designations. Which are in common use for satellite services? (06 Marks) [. What is INTELSAT? How it covers the International traffic? (04 Marks) c. State and explain the Keplers 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) 3rr b. Explain the Keplerian element set with their meanings with resp,eet4e sa c. What are antenna look angles? How these are determined? =o aa d. Determine which of the followings years are leap years: c!. . .ji ,.: c i) 1987 ii) 1988 iii) 2000 iv) 2100. tt"" (04 Marks) !}: )q /{, 3a. Explain atmospheric and ionospheric losses for satellites. (06 Marks) b. Briefl y explain uplink-and-downlink rain-fade margin. (04 Marks) i- 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 rain height 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) EO 4 a. What is a satellite transponder? With a neat diagram explain the overall frequency arlangement 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 satellite --.t satelelization. (10 Marks) = PART B - z.e, ;8 5 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 .i 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 [B]rn = 75.56. (04 Marks) c. Explain the frame and burst formats for a TDMA system. (10 Marks) I of 2
  • 7. 06EC6627a. Explain: i)Transpondercapacity ii)Frequency and polarization. iii)Bit-rate for digital TV. (10 Ma*s) b. Explain in detail the satellite mobile services. (10 Marks) Write short notes on any three choosing any one from c. and d. a. Geo- stationary orbit. b. VSAT and its applications. c. GPS and its uses. d. Radarsat. (20 Marks) 2of2
  • 8. / USN 06EC661 Sixth Semester B.E. Degree Examination, Jrune 2Ol2 Programming in G++ Time: 3 hrs. Max. Marks: 100 Note: Answer FIVE full questions, selecting at least TWO questions from each part. PART -A la. Explain enumeration data types with examples. (04 Marks) b. What do mean by dynamic initialization of a variable? What is the primary difference I between static and dynamic memory allocation. (08 Marks) C. Write a note on #define directive and const modifier. (04 Marks) d. Explain the difference between the four objects defined below: i) int ival = 1024 -- ll ii) int *pi2 = new int (1024) .EA iii) 1n1 *pi = &ival iv) int *pi3 = new int [024]. (04 Marks) a. What is pointer? Explain the advantages of a pointer. Indicate the difference between address operator and indirection operator. (10 Marks) b. What are the basic operations performed on string. Write a program in C++ to find the Iength of the string using string type. (06 Marks) c. Give lhe output of the following: void main( ) { int i=4, j = -1, k =0, w, x, y, z: ni i^ w=ill: llr; x=i&&j&&k; o- ll y=illjaah z=i&&j llk; q; cout <<w<<x<<y<<z; ) (M Marks) E* a. What are bitwise operators? Explain the left shift and right shift operations with examples. (04 Marks) ia = 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++ to ;.i count the number of vowels in a given string. (10 Marks.l z a. Explain the call by value and call by reference parameter passing method with an example of each. (10 Marks) E b. Write a recursive function to find factorial of n numbers. (05 Marks) E c. What is a function? Mention the advantages of using functions. (05 Marks) lof2
  • 9. I I 06EC661 PART-B5a. What is an exception? With the help of example explain how the try block and catch block works. (10 Marks) b. Write a C++ program to illustrate the process of catching all uncaught exceptions through in a try block. (10 Marks)6a. Explain parameterized constructors. Develop a C++ program to implement parameterized constructor. (10 Marks) b. Explain the following features of OOPs: i) Classes ii) Objects iii) Polymorphism iv) Inheritance v) Encapsulation. (10 Marks)7 a. What is an operator over loading? Write a C++ program to add 2 complex numbers by over loading the operator +. (10 Marks) b. Explain how an array of objects can be created and members of the objects are accessed. Give example. (I0 Marks)8 a. Explain single and multilevel inheritance with examples. (10 Marks) b. Briefly explain public, private, protected inheritance. (06 Marks) c. Write a note on base class and derived class. (04 Marks) 2of2