3rd Semester Electronic and Communication Engineering (2013-June) Question Papers


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3rd Semester Electronic and Communication Engineering (2013-June) Question Papers

  1. 1. IUSN IOMAT3T Third Semester B.E. Degree Examination, June/July 2013 Max. Marks:100 (07 Marks) (06 Marks) , 9 :h 96, .g 6 -ir'E ^ != 6d .r= 6t= = -!2 ;-E 3t o< o z o at least TWO questions from each parl PART - A I a. Obtain the Fourier series exoansion of fr*t=l '' if 0<xl' und hence deduce [2r-x, if n< x<2x -ntllIthdt -= -* -* ^*.""-' g l, 3, ' 52 "" "' b. Find the halfrange Fourier sine series of it*l = { *' 'l^ o-:* '% |.n-* il /,<x<t Time: 3 hrs. Note: Answer FIVE full questions, selecting constant. a. Using method of leastoI leas square. I1I a x 2 3 4 5 v 0.5 2 4.5 8 12.5 b. Solve the following LPP graphically: Minimize Z=20x+l6y Subject to 3x+y>6, x+y>4, x+3y>6 andx,y>0. c. Use simplex method to Maximize Z: x+ (1.5)y Subject to the constraints x + 2y 3 160, 3x + 2y < 240 and x, y > 0. c. Obtain the constant term and coeffrcients of first cosine and sine terms in the expansion ofy from the followins table: (07 Marks) -.: .,: t-t/^ 2 a. Find the Fourier transform of p1x;=]o ^^' ,^l - o and hence deduce Isrn-lcosxd*=1. L 0. lxl>a j x' 4 (07 Marks) b. Find the Fourier cosine and sine transform of(x): t"-a*, where a > 0. (06 Marks) c. Fincl the inverse Fourier translorm of e-" . (07 Marks) 3 a. Obtain the various possible solutions of one dimensional heat equation u1 : c2 u** by the method ofseparation ofvariables. (07 Marks) b. A tightly stretched string of length ,t with fixed ends is initially in equilibrium position. It is se1 ro vibrare by giving each point a velocity ,..4[+). Find the displacement utx. t). c. Solveu*,,*uyy:0 givenu(x,0):0, u(x,1):0,u(1,y):0andu(0, y.):r., *n:[Hll? fit a curve y - axb for the following data.. . (07 Marks) (07 Mar.ks) x 0 600 120' 180" 240" 300 360" v 7.9 7.2 3.6 0.5 0.9. 6.8 7.9 1of 2 (07 Mrrks)
  2. 2. 5a. b. method lrt , ,1 A=l l 3 0 l. l, o -4] Use f,(o) = [1, 0, 0]r as the initial eigen vector. PART _ B Using Newton-Raphson method find a real root of x * logrox :3.375 near 2.9, 3-decimal places. Solve the following system ofequations by relaxation method: 12x+y +z=31, 2x+8y -z=24, 3x + 4y + l0z = 58 1OMAT31 corrected to (07 Marks) (07 Marks) c' Find the largest eigen value and corresponding eigen vector of following matrix A by power (06 Marks) 6 a. Inthe given table below, the values ofy are consecutive terms ofseries ofwhich 23.6 is the fthe series.6rh b. Construct difference formula. find the first and tenth terms o x 3 4 5 6 7 8 9 v 4.8 8.4 t4.5 23.6 36.2 52.8 73.9 an interpolating polynomial for the data (07 Marks) given below using Newton's divided (07 Marks) c. Evaluate [--I "0" by Weddle's rule taking 7-ordinates and hence find log"2. (06 Marks) jl+x' x 2 4 5 6 8 l0 flx) l0 96 196 350 868 1746 Solve the wave equation utt ='{ux* subject to u(0, t):0; u(4, t):0; u(x,0):0; u(x, 0) : x(4 - x) by taking h: 1, k = 0.5 upto four steps. (07 Marks) Solve numerically the equation # = # subject to the conditions u(0, 0 : 0 : u(l, t), t > 0 and u(x, 0) = sin 7rx, 0 < x < 1. Carryout computations for two levels taking h : / and (07 Marks) for the following square mesh with boundary values (06 Marks) Fig.Q7(c) la. b. 8a. b. c. Find the z-transform of: i) sinhn0; ii) coshn0. Obtain the inverse z-transfor. of 8" (22-1)(42-r) Solve the following difference equation using z-transforms: !n+zl2!n+t +yn:n with Yo:Yr =0 2 of2 (07 Marks) (07 Marks) (06 Marks)
  3. 3. E I o o i ,q o q o o. o o ... o z o o E USN ,,, Time: 3 hrs. 10E532 Max. Marks:100'. - :" ., Third Semester B.E. Degree Examination' June/July 2013 Analog Electronic Gircuits Note: Answer FIVE full questions, selecting at least TWO questionsfrom each part :r I + .E o 8-, o oo a.j PART-A a. Explain the following terms with respect to semiconductor diode: i) Diftrsion capacitance . -:...' ii) 'Tr4nsition capacitance and ;.. ,' iiD Rdveise recovery time. -..) ' (06 Marks) b. For the clipping circuit shown in Fig.Q.l(b). Obtain its transftrlharacteristics to the scale for a ramp input.which varies from 0 to 50 voits. Indicate slopes at different levels and assume ideal diodes, (lo Marks) * ,., >-gx Fig.Q.1(b) -9- Design an ideal clamper circuit to obtaiiithe output waveform as shown in Fig.Q.1(c) for the -i.,-r l-n,+ /Od Marksgiven input. (04 Marks) b. Fig.Q.2(b) Design an emitter-bias network using the following data: Icq- ll2lcr*0, Vcee : l/2Ycc, Vcc:20V, I615nj: 10mA, B : 120 and Rc = 4Re ' (06 Marks) . I of2 +
  4. 4. 3a. b. c. Define h-parameters and hence derive h-parameter model ofa CE-BJT. State and prove Miller's theorem. i) FET and BJT and ii) Enhancement and depletion MOSFET ; 10E532 (06 Marks) (04 Marks) (04 Marks) (10 Marks) i) g*; ii) ra; (10 Marks) For the circuit shown in Fig.Q.3(c), the transistor parameters are hib : 22{2' hn: -0.98, h.r : 0.49 MA/V and h*:2.9 x 10{. Calculate: i) Input resistance; ii) Output resistance; iii) Current gain; iv) Voltage gain; v) Overall voltage and current gain. (10 Marks) c- "L- (L: t 1+o Fig.Q.3(c) Explain the low frequency and high liequency response ofa RC coupled amplifier. (10 Marks) Describe Miller's effect and derive an equation for Miller input and output capacitance. (06 Marks) Calculate the overall lower 3db and upper 3db frequency for a 3 stage amplifier having an ll( -1 J 4a. b. c. 5a. b. 6a. b. la. b. individual frequenry fr : 40 Hz and fz:'2 MHz. PART - B Explain and analyze with the help of circuit a cascade BJT amplifier and list its advantages. What are the effects olnegative feedback in arnplifier? Show how band,riatn of an(I0#iif,i] increases with negative feedback. (10 Marks) Explain the operation of a class B push-pull amplifier and also show that its e[ficiency is 78.50Yo and max power dissipation condition. (10 Marks) With a neat circuit diagram, explain the operation of a transformer coupled class A power amplifier. (10 Marks) State Barkhausen criteria for sustained oscillations, apply this to a transistorized Weinbridge oscillator and explain its operation. (10 Marks) Explain workin!. of a Hartley oscillator. In a Hartley oscillator L1 = 20 MH, L2:2mH and C is a variable. Find the range of C for liequency is to be vaiied from lMHz to 2.5 MHz. (10 Marks) 8 a. List the difference between: ii, JFET and MOSFET. b. For the circuit shown in Fig.Q.8(b) V6sq: -2.5V and Ig,q:2.5 mA find: iii) zi iv) zo and v) A,. Assume Ioss: 8rnA, Vp: -6V and Yos:20 mO. *t9 V >'> KiJu HVo l) D nI ry)u Fig.Q.8(b) 2 of 2
  5. 5. USN 10ES33 (08 Marks) (04 Marks) (08 Marks) Third Semester B.E. Degree Examination, June/July 2013 Logic Design q E 2 8v o.o -9= L;j o,i a,q ; o z ts o. E Time: 3 hrs. Max. Marks:100 Notel Answer FIVE full questions, selecting atleast TWO questions lfrom each part. PART - A a. Simplify the following expression using Karnaugh map. Implement the simplified expression using the gates as indicated. (a, b, c, d) : Im(0, 1,2, 5, 6,7, 8,9, 10, 13, 14, 15) using onlyNAND gates (A, B,C, D):nm (0,3,4,7,8, 10, 12, 14)+2d(2,6)usingonlyNORgates. (l2Marks) b. Design a logic circuit that has 4 inputs,,the output will only be high, when the majority of the inputs are high, use K map to simplify. (08 Marks) a. Simplify using the Quine - Mcclusky minimization technique. Implement the simplified expression using basic gates V: (a, b, c, d)::(2,3,4. 5. 13, ls) + Id(8,9, 10, t1). (t2 Marks) b. Simplify the logic function given below using variable entered mappings (VEM) technique f(A, B, C. D) : Im(0, 1, 3. 5. 6. 11, 13.1 + Id(4, 7). (08 Marks) a. With the aid of block diagram, clearly distinguish between a decoder and encoder. (04 Marks) b. Design a combinational logic circuit that will convert a straight BCD digit to an excess - 3 BCD digits i) Construct the truth - table ii) Simplify each output function using k map and write the reduced equations iii) Draw the resulting logic diagram. (12 Marks) c. Implement a full substractor using a decoder and NAND gates. (04 Marks) 4 a. Implement the following Boolean function using 4 : 1 multiplexer _ F(A, B, C) = Xm (1, 3, 5, 6) (04 Marks) b. Design a 2 bit comparator. (08 Marks) c. What is a look ahead calry adder? Explain the circuit and operation ofa 4 bit binary adder with look ahead carry. i ,.:i .rr . (08 Marks) -.::. i l PART-B ; 5 a. Differentiate sequential logic circuit and combinational logic cfuciiit;.. ,,' . , (04 Marks) b. Explain with timings diagram the uorkings ola SR latch as a swirch debouncer. (08 Marks) c. Explain the workings of a master - slave JK flip flop with functional table and timings diagram. (08 Marks) 6 a. With the help of a diagram, explain the following with respect to shift register i) Parallel in and serial out ii) Ring counter and twisted rings counter. b. Explain the workings of 4 - bit asyncluonous counter. c. Derive the characteristic equation of SR, JK, D and T flip - flops. 1of2
  6. 6. I 10ES33 7 a. With a suitable example, explain the mealy and Moore model of a sequential circuit. (10 Marks) , b. Design a synchronous counter using JK flip-flops to count the sequence 0,1 .2,4,5, 6. 0. 1r.2 At , use static diagram and state table. 1lo naa$$' //a ht V6^. Design a clocked sequential circuit that operates according to the state diagrEr$hbwn. -/-p lmplement the circuit using D - flip - flop. - . l[2lt{arks) .'r", 'F>.r1 ^ -, & &&; qE $>,r,t:*t - /'ryn ol.;ultt "ry,. wa, b. wittr a suitable, example'6{ appropriate..ctbtp diagranl explain how to recop.ize a ' particular sequence. Ex l0ll."# ,. .,F" (08 Marks) dE. ^ : y'" L-/.A *. * *),r. ,r. + / -' J/,l !$ 'r1 . -/.1ti !r * L/*, r-' )*/ r o)' t"r ,.l ' r--'" .+" (lJ r -.-.. .f1 .z- .^ :' -$J^ .", ' , .-ryb Y:-.i * '. 1- ^, J, r€i 17 ,{ (.}"* !v -( i {$ '1 :"^' {"1 t-/r 'r'.- i " .- 'r {.:l "."{k" '{;-X' ' '.'. */ 2 of2
  7. 7. I]SN 06E534 (08 Marks) Q2 (c), draw the dual (08 Marks) L]- (04 Marks) in Fig. Q3 (b) Third Semester B.E. Degree Examination, June/July 2013 Network Analysis Time: 3 hrs. Max. Marks:100 Note:I. Answer FIVE full questions, selecting at leosl TWO questions from each part. 2, Standard notstions are used. 3. Missing dato be suitably ossumed. PART_A 1 a. Find the voltage to be applied across AB in order to drive the current of 10 A into the circuit using star-delta transformation Fig. Q1 (a). (06 Marks) b. Use mesh analysis to evaluate current I in the circuit shown in Fig.l (b). (06 Marks) c. Determine the current and voltage across each resistor using node voltage method for the network shown in Fig. Q1 (c). (08 Marks)I :h .e6 E= =B o. d- 9r i; -;o o. at tr< .i ..i E BI 2A 1rL Fig. Ql (a) 2 a. Explain briefly graph, trees, links and cotrees of the network with suitable examples. (04 Nlarks) b. Write the tie-set schedule for the network shown in Fig. Q2 (b), using tie set schedule obtain the equilibrium equations on loop current basis. c. Explain "Duality as applied to network, for the network shown in Fig. network. 6a 0- E rL Fig. e2 (c) Fie. Q2 (b) State and explain Millman's theorem. Using superposition theorem determine the cunent I in the network shown given V = 10cos(105t+45), i, =16r/2r1rr105t and i, =10cos10't 3a. b. c. 4a. b. '12- Fig. Q3 (b)f lB. vJ (u, In the single current source cicuit shown in Fig. Q3 (c), find the voltage V* inter change the current source and resulting voltage V*, is the reciprocity theorem verified? (06 Marks) State and explain Nortons theorem. (04 Marks) Prove that an alternating voltage souce transf'er maximum power to the load when the load impedance is the complex conjugate ofthe source impedance. Fig. Ql (c) nig. Q1 (b) Fie. Q2 (c) a= 6D?0 A 1of2 (06 Marks)
  8. 8. ---1 06E534 4 c. For the circuit shown in Fig. Qa (c), find the value of z that will receive maximum power also determine this power. (10 Marks) -Jr o ./L : Fig. Qa (c) Fig. Q5 (b) PART-B 5 a. Define Q of a series resonanl circuit. obtain hallpower frequencies in terms olQ and show ' that the resonance frequency is the geometric mean ofthe halfpower frequencies. (10 Marks) b. Find the values ofl- for which the circuit shown in Fig. Q5 (b) resonant at ri frequency of 500 rad/sec. (06 Marks) c. A fixed condenser is placed in parallel with a fixed resistance connected in series with a x^tri.variable inductor show that for resonance X='tc +"1"c -g:. (04 Marks) 2 2 6 a. In the network.shown in Fig. Q6 (a), a steady state is reached with the switch K is open at t : 0. The switch is closed. For the element values given determine the values of Va(0 -) and Va(0 l-) (ro Marks) Vr I rt -'.' Fig, Q6 (a) Why we need to study initial cohditions? A parallel R - L circuit is energized by a current source of 1 A. The switch acroSs the source is opend at t : 0 solve for V. 9I and o v all at t : o* irR = 1oo e:, L -i.;. dt ,11r".u, Derive z-parameters in terms of Y parameters. (07 Marks) Find z-parameters foi the two-port network shown in Fig. Q7 (b). (06 Marks) 5v b. 7a. b. n+ + - t J4o seo f Vr { 5,00 u;f +t{ l, Fig. e7 (b) Fie. e7 (c) c.. Find ABCD constants and show that AD - BC : I for the network shown in Fig.e7 (c). (07 tMarks) a. Synthesize the periodic wave form shown in Fig. Qs (a) and find its Laplace transform and prove any formula used. (to Marks) b. Using convolution theorem find the Laplace inverse of F(s) = 2 of2 Fig. Qa (c) Fig. Qs (b) Fig. Q8 (a) (s+l)(s+2)(s+3.1 (10 Marks)
  9. 9. USN 10IT35 (07 Marks) (07 Marks) (06 Marks) (07 Marks) (08 Marks) (06 Marks) Time:3 Third Semester B.E. Degree Examination, June/July 2013 Electronic lnstrumentation Max. Marks:100 Nole: Answer FIVE full questions, selecting ot least TWO questions from eoch part. I a. Explain with suitable example u".u*ffifr",r,o,r. (0s Marks) b. A Permanent Magnet Moving Coil instrument (PMMC) with Full Scale Deflection (FSD) of 100 pA and coil resistalce is 1 KO is to be connected into a voltmeter. Determine the required multiplier resistance if the voltmeter is to be measure 50 V at full scale. Also calculate the applied voltage when the instrument indicates 0.8, 0.5 and 0.2 of FSD. (08 Marks) c. Explain with neat circuit diagram and wave forms full wave rectifier tlpe AC voltmeter. o E .sA d9! .e(! -a'I^ 9'= ,i .9 o!o E-3 og U< -..i .i a z E 2a. b. Explain basic operation of digital multimeter with neat block diagram. Meter 1DVM1. c. Explain with neat block diagram Digital Frequency Meter. PART - B Explain with neat block diagram, operating principle of function generator. Elaborate with neat block diagram, conventional standard signal generator. Suppose the converter can measure a maximum ol 5 V. i.e. 5 V conesponds to the maximum count of 11111111, if the test voltage is Vin: 1 V. Show the steps take place in the table format in the measuement for the successive approximation tlpe Digital Volt 3a. b. 4a. b. ..:c' 5a. b. Explain sweep or time base generator with neat circuit diagram and wave forms, for a continuous sweep CRO and triggered sweep CRO. (t2 Marks) Explain dual trace oscilloscope with neat block diagram. (08 Marks) Discuss need for delayed sweep in digital storage oscilloscope. (04 Marks) _[xplain basic principle of sampling oscilloscope with neat diagram and *r* for.fiu ,u.ury Explain two tlpes of storage techniques used in storage oscilloscope with neat diagram. (10 Marks) c. Explain with neat block diagram and waveflorms, frequency synthesizer in signal generators. I of2 (06 Marks)
  10. 10. rr 10IT35 6 a. Derive an expression for galvanometer current (Ig) when the wheatstones bridge is unbalanced. (05 Marks) b. An unbalanced wheat stones bridge is shown in Fig. Q6 (b). Calculate cunent in the galvanometer. (05 Marks) I . // I r'sP-Y L -| $l -4ZEn-l ,r R e.-'" L/ '' -r- rov -f; ;]3;7 tr; l/IV Fig. Q6 (b)-f rts. ve (u/ . i:.., c. Derive an ex@;ion for Lx and Rx which is a series impg{iurire in the Maxwell's bridge. And find series 6qu -ivalent unknown impedance, when C_r=0.0i pl Rr:470 KQ. Rz:5.1 KQ, Rl : I 00 KO ( lo Marks) (05 Marks)7 a. List at least five advantaS$[electrical transducer. b. A displacement transducer ';ifth a shaft stro(eUf3.0 inch, is applied to the c cuit as shown in Fig. Q7 (b) below. The total resistance ott$e potentiometer is 5 KO, the applied voltage Vt is 5 V. When the wiper is at 0.9 furch from B. What is the value of output voltage V6. .. (05 Marks) NiFt^ ' wI 'l ,v"?,I 'i1 :i, rr E'ic r)7 /l'. .-i:, Fig. e7 (b) c. Define Gaugg fd$6i. Derive expression for gauge factor ot-..briunded resistance wire strain gauge. .-,'31 - ,t:,: (loMarks) A a. Explaifr,.bhbto transistor. With neat diagram and output characteriSiticst How is it used as a transduber? (05 Marks) b. I"S.zrt least five classifications of digital displays. _' . (05 Marks) c,.t"tisi out the requirement of a dummy load. Ald explain measurement of power by means of - l;'a bolometer bridge. . ltgtrlarks;r 2 of2
  11. 11. USN Note: Answer FIVE full questions, selecting at least TII.O questions from each part. 10E536 Max. Marks:100 (08 Marks) (05 Marks) /.trz space if V = --ll - ar P( I . 2. 3). x' + I (07 Marks) Third Semester B.E. Degree Examination, June/July 2013 Field Theory Time: 3 hrs. o E E0) YO- -z' i d.&Eo- !g -^o o.U rJ< -i .i o z o E . PART-A I a. State 4nd prove Gauss's Divergence theorem. (06 Marks) b. State and explain the electric field intensity and obtain an expression for electric field intensity due.to an infinitely long line charge. (08 Marks) c. A charge of .-0.3 pC is located at A(25, -30, 1 5) crq and a- seqond charge of 0.5 pC at B(-10, 8, 12) crn-'Find E at i) the origin i, P(15, 20, 50) cm. (06 Marks) 2 a. Discuss with relevant equations the potential field ofa syitem of charges and hence obtain the potential field of a ring o f unilorm line charge density. (08 Marks) b. Discuss current and current density and derive the-.gxpression for continuity "quu,riti *".u"t c. Given the field E : 40 xya,+21xza9+2a,Y lm, ialoulate the potential between the two points P(1, -1, 0) and Q(2, 1, 3). (06 Marks) 3 a. State and prove the uniqueness theorem. b. Derive Poisson's and Laplace's equations. .._ a c. Calculate numerical values for V and Sv at point P-in free 4 a. Derive an expresgiori for magnetic field intensity at a polirt P due to an infinitely long straight filamgnt darrying a current I. Also obtain the magnetic field intensity caused by a finite lengthcunent filament on the z-axis. (08 Marks) b. In an infuritely long coaxial cable carrying a uniformely current I if'&e imer conductor and -l in the outer conductor, find the magnetic field intensity is a function of radius and sketch the field intensity variation. c. Discuss the scalar and vector magnetic potentials. PART _ B Discuss the force on a differential current element (07 Marks) (05 Marks) and also obtain the expression for force. (08 Marks) b. Given a ferrite material which we shall specifr to be operating in a linear mode with B = 0.05 T, let us aSSUrle pr: 50, and calculate values for x-, M and H. (06 Marks) c. Define inductance and derive the expression for inductance of a to,rodial coil of N turns and a current l. ...L,":.t-':) -; ,. (06 Marks) -' .t-- .:i // 5. a. 1 of2
  12. 12. r1 10E536 6 a. List the Maxwell's equations in point and integral forms for time varying freld. (06 Marks) b. Explain the retarded potentials. (08 Marks) c. Let p=105 FVrL e=4x10+F/nL o=0 and Su =0. Find K so that each ofthe following r) D = (oax - zyay + 2za"1c trn' ) t, H=(Kxa, +l0yar-252a,) Nm ^ VY' ii) E=(2oy-Kt!- vrm +-r) /'!' j" *b.I:=(r*r"1out)a. A/m p, (o6Markg'-$x=1y+2xtv"t) a" Atm _kt (06 Marks) '1f,- G,' 7 a. Start@-om Maxwell's equations, obtain the wave equations in free6qgtd. (07 Marks) b. Derivel@xpression for depth of penetration. ^t (07 Marks) c. Find the' lpfrh of penetration at a frequency of 1.6 F$D in aluminium, where o=3S.2Mdr$yd F, =t.Alsofindy,LandVp. ,63fe, (06Marks) L4,, ', /i I a. Derive the expresildS.for reflection and transmissipg.olm"i.nt. for normal incidence at pair of fields satisfies Maxwell's equations: I O = (Oa. -2ya, + 2za"nC /m2) Derive the expressi$.{br rellection and transmisslpt coBfficients for normal incidence at the boundary betweenlfg{ielectrics. t# (09 Marks) do*-for rel enlVodie drine@,b. Write a note on standing rf&, ratio. interfice yield a 1.5 m spacing behftpprfixima vdth the fust maximum occuning 0.75 m from the interface. A standing Wftft/}fiio of 5 is measured. Determine the intrinsic - impedance n.of tlre unknown (05 Marks) D. Wrrte a note on $ancmg WeFatlo. 0.. . (06 Marks) c. A uniform plane wave in"6iirpartially rqflpg6y' from the surface of a material whose properties are unknown. Mea${ilnqrts of# electric field in the region in front of the /frv./l ,4, "t?-#" '51"" "%.* ^os-,{. .}- ry- zrV,U ^-.17f *-'l -.- t t. v ^ --! r"a- "'11*',*,. ){ 7 2 of2