
	Trending ▼ ICSE CBSE 10th ISC CBSE 12th CTET GATE UGC NET Vestibulares ResFinder

EC Gate Paper 2012

14 pages, 0 questions, 0 questions with responses, 0 total responses,

	cbsinghmb	+Fave Message
	Profile Timeline Uploads

Home > cbsinghmb >

Formatting page ...

2 012 E C: ELECTRONICS AND COMMUNICATION ENGINEERING Duration: T hree Hours Maximum Marks: I 0 0 Read the following instructions carefully. 1. Do not open the seal o f the Question Booklet until you are asked to do so by the invigilator. 2. Take out the Optical Response Sheet (ORS) from this Question Booklet w ithout breaking the seal and read the instructions printed on the O RS carefully. I f you find that the Question Booklet Code printed at the right hand top comer o f this page does not match with the Booklet Code on the ORS, exchange the booklet immediately with a new sealed Question Booklet. 3. On the right h alf o f the O RS, using ONLY a b lack ink ball point pen, (i) darken the bubble corresponding to your test paper code and the appropriate bubble under each digit o f your registration number and (ii) write your registration number, your name and name o f the examination centre and put your signature at the specified location. 4. This Question Booklet contains 20 pages including blank pages for rough work. After you are permitted to open the seal, please check all pages and report discrepancies, i f any, to the invigilator. 5. There are a total o f 65 questions carrying 100 marks. All these questions are o f objective type. Each question has only o ne correct answer. Questions must be answered on the left hand side o f the O RS by darkening the appropriate bubble (marked A, B, C, D) using ONLY a b lack ink ball point pen against the question number. F or each question darken the bubble o f the correct answer. More than one answer bubbled against a question will be treated as an incorrect response. 6. Since bubbles darkened by the black ink ball point pen c annot be erased, candidates should darken the bubbles in the O RS v ery carefully. 7. Questions Q .l - Q.25 carry 1 mark each. Questions Q.26 - Q.55 carry 2 marks each. The 2 marks questions include two pairs o f common data questions and two pairs o f linked answer questions. The answer to the second question o f the linked answer questions depends on the answer to the first question o f the pair. I f the first question in the linked pair is wrongly answered or is unattempted, then the answer to the second question in the pair will not be evaluated. 8. Questions Q.56 - Q.65 belong to General Aptitude (GA) section and carry a total o f 15 marks. Questions Q .56- Q.60 carry 1 mark each, and questions Q .61- Q.65 carry 2 marks each. 9. Unattempted questions will result in zero mark and wrong answers will result in N EGATIVE marks. For all 1 mark questions, % mark will be deducted for each wrong answer. For all 2 marks questions, % mark will be deducted for each wrong answer. However, in the case o f the linked answer question pair, there will be n egative marks only for wrong answer to the first question and no negative marks for wrong answer to the second question. 10. Calculator is allowed whereas charts, graph sheets or tables are N OT allowed in the examination hall . 11 . Rough work can be done on the question paper itself. Blank pages are provided at the end o f the question paper for rough work. 12. Before the start o f the examination, write your name and registration number in the space provided below using a black ink ball point pen. N ame Registration Number EC-C J4QAK--t=&~~ EC 'fAu._A I ~ I \ I ~I &-I o I r l \ 1/20 201 2 ELECTRONICS & C OMMN. ENGG. - EC Q . 1 - Q. 25 carry one mark each. With initial condition x (l) = 0 .5, t he solution o f the differential equation, Q .1 dx . t -+x=t IS dt 1 (A) x =t-2 ( B) X 2 1 =t - 2 T he u nilateral Laplace transform o f f (t) is Q.2 (A) - 2 s ( s + s + 1) (C) 1 s + s+1 2s + 1 ( B) - ---=---...,.... 2 2 ( s + s + 1) 2 s 2 (s + s + 1) ( D) p 2 (A) 44.2 W > ;) / 1 ~ Q.S b y a c urrent 5 cos(l 00Jrt + 100) A is w (D) 125 W c, I ( B) a s tep function ( D) a n i mpu lse function (A) zero JC) an exponentially decaying function ~ 2 1 . .lx ~ 5<.:. 0C:: t n ::x.., t~ o ~ )-/~\tfj~c?,~j ~ y fi- (s + s+l) , (C) 62.5 (B) 5 0 W s "- 2 s+1 2 In the following figure , C 1 a nd C 2 a re ideal capacitors. C 1 h as b een c harged to 12 V b efore the ideal switch S is closed a t t = 0. T he c urrent i(t) for all t is Q.4 c; . T he u nilateral Laplace transform o ft f (t) is 2 The average p ower d elivered to a n i mpedance ( 4 - j3) Q.3 I t ( D) x =2 (C) T he i-v c haracteristics o f t he diode in the circuit given b elow a re i={v;0~ ..... ~~~ ~ 7 A , v ?:0.7V O A, v <0.7V 1 kn + v T he c urrent in the circuit is (A) 10 m A Q .6 (C) 6 .67 m A ( D) 6 .2 m A T he o utput Y o f a 2 -bit comparator is logic 1 w henever t he 2-bit input A is greater than the 2-bit input B. T he n umber o f c om binations for w hich t he output is logic 1, is (A) 4 EC-C .{B) 9.3 mA (B) 6 (D) 10 2/20 2012 Q.7 E LECTRONfCS & C OMMN. E NGG.- EC Consider the given circuit. In this circuit, the race around (A) does not occur (C) occurs when C LK = 1 a nd A = B = 1 Q .S (B) occurs when C LK = 0 (D) occurs when C LK = I and A = B = 0 T he electric field o f a u niform plane electromagnetic wave in free space, along the positive x direction, is given b y E = 10 (a Y + j az) e - 125 x . T he f requency and polarization o f the wave, j ~ ot.. respectively, are (A) 1.2 GHz and left circular ' (C) 1.2 G Hz and right circular Q.9 (B) 4 Hz and left circular (D) 4 Hz a nd right circular A plane wave propagating in air with E =(Sax + 6ay +5az)eJ(wt+3 x- 4 y) V /m is incident on a perfectly conducting slab positioned at x:::; 0 . T he E field o f the reflected wave is (A) ( -Sax - 6aY -5az)eJ(wt+ 3 x+ 4 Yl V /m (B) ( -Sax+ 6 ay - 5aJe 1("'1+ 3 x+ 4 y) V /m ' ' ' ( c) ( - Sax- 6 ay- 5 az ) e j(rot-3x-4 y) V/m (D) ( -Sax + 6aY - 5a z )eJ(rut- 3 x- 4 y) V /m Q . 10 In a baseband communications link, frequencies upto 3 500 H z a re used for signaling. Using a raised cosine pulse with 75% excess bandwidth and for no inter-symbol interference, the maximum possible signaling rate in symbols per second is (A) 1750. Q.11 (C) 4 000 (B) 2625 ..{D) 5250 The power spectral density o f a real process X(t) for positive frequencies is shown below. The values o fE[X\t)] a nd I E [X(t)JI, respectively, are Sx(w) 6 0 9 10 11 w (10 3 rad/s) (A) 6000/n-, 0 (C) 6400/n-, 20 !(Jr.fi) EC-C (B) 6400/Jr, 0 (D) 6000/Jr, 2 0/(Jr.fi) 3/20 201 2 Q.J 2 ELECTRON ICS & COMMN. ENGG. - EC T he c urrent i 6 t hrough the base o f a s ilicon npn t ransistor is 1 + 0 .1 cos ( I 0 000 n t) m A . At 3 00 K, the r 7 f in the small signal model o f t he transistor is ib B C ~--~~ .---.~ ro (A) 2 50 Q . 13 e -tr / 2 n (C) 25 n (D) 22 .5 n .....\ . ._,..{ .z.., "' (B) e tr / 2 ~ (C) X (D) 1 T wo independent r andom v ariables X and Y a re uniformly distributed in the interval [- 1, 1]. T he p robability that max[X, Y] is less than l/2 is (A) 3 /4 Q . 15 (B) 27.5 I f x = ~ , t hen the value o f x x is { (A) Q . 14 n (B) 9/16 (C) l /4 (D) 2 /3 G iven f (z ) 1 2 =- +-1 - - +-3 . I f C is a counterclockwise path in the z-plane such that Iz +II= 1, the value o f - zz 1 - --.! f ( z )dz is 2n J T c (A) - 2 Q .16 (B) - 1 (C) 1 (D) 2 In the circuit shown below, the current through the inductor is / 'V 0 (~0> ~ (Y~ 2 ( A ) - ---A l +j (B) --=--!.___A 1 +) 1 (C) - -A 1 +) (D) 0 A ~ {/ QL ~ ~-I\ - ------------------------------------------------------------------------EC-C 4/20 2012 Q . 17 E LECTRONICS & C OMMN . E NGG. - EC T he impedance looking into nodes 1 and 2 in the given circuit is ib 1kD (A) Q. 18 son ( B) 100 n (C) 5 k Q ( D) 10.1 i ll A system with transfer function G (s) = 2 ( s + 9 )(s + 2) ( s+1)(s+3)(s+4) is excited by s in(cut) . T he steady-state output o f t he system is zero at (B) cu = 2 rad/s (D) cu = 4 rad/s (A) cu = 1 rad/s (C) cu = 3 rad/s Q. J9 In the sum o f p roducts function f (X, Y, Z ) (A) X Y, X Y - - (B) - (C) X YZ , XYZ , XY Q.20 X Y, X Y Z , X Y Z (D) X YZ, X YZ, X Y Z , X Y Z I f x [ n ] = (1 I 3)1"1 - (1 I 2)" u[ n] , t hen the region o f c onvergence (ROC) o f its Z-transfonn in the Z-plane will be CA) Q .21 = L)2, 3, 4, 5 ), the prime implicants are t <Iz I<3 &CB) t <I z I<+ ~ cq +<I z I< 3 CD) t <I z I etc- ~'2-. Y---- ~~,: ~ The radiation pattern o f an antenna in spherical co-ordinates is given b y F ( B)= cos 4 e; 0::;; e : ; :rr I 2 The directivity o f t he antenna is (A) 10 dB Q .22 ( B) 100 n ( D) 18 dB (C) 143.3 n (D) 43.4 3 n A source alphabet consists o f N symbols with the probability o f t he first two symbols being the same. A source encoder increases the probability o f t he first symbol by a small amount & and decreases that o f t he second by & . A fter encoding, the entropy o f t he source (A) increases (C) increases only i f N = 2 EC-C (C) 11.5 dB A coaxial cable with an inner diameter o f 1 m m and outer diameter o f 2.4 m m is filled with a 10 -9 dielectric o f r elative pennittivity 10.89. Given 1-'o = 4:rrxl0 - 7 H /m, &0 = - - Fjm , the 36:rr characteristic impedance o f t he cable is (A) 330 n Q .23 (B) 12.6 dB (B) remains the same (D) decreases 5/20 2012 Q .2 4 ELECTRONICS & C OMMN. E NGG.- EC In the circuit shown A~ 8~ ~)c LCM<()~ ~-=f0ii A~ (A) Y The diodes and capacitors in the circuit shown are ideal. The voltage v(t) across the diode D1 is C1 02 C2 (D) 1 -sin(mt) (C) 1 -cos(mt) (B) sin ( m t) (A) c os(mt)-1 Q. 26 to Q. 55 carry two marks each. Q.26 The direction o f vector A is radially outward from the origin, with IA I= k r" where r 2 = x 2 + y 2 + z 2 and k is a constant. The value o f n for which 'V A= 0 is (A) -2 Q.27 (C) 2/3 (B) 112 (D) 3/4 (C) 0 ( D) 1 Consider the differential equation The numerical value o f dyl dt (A) -2 EC-C ( D) 0 A fair coin is tossed till a head appears for the first time. The probability that the number o f required tosses is odd, is (A) 1/3 Q.28 (C) 1 (B) 2 is t=O+ (B) -1 - ( ?'tl)tl (D) Y = AB+C (C) Y =(A+B)C Q.25 -tG ( B) Y =(A+B)C = AB +C 6/2 0 2012 Q .2 9 E LECTRONICS & C OMMN. E NGG.- EC A ssuming both the voltage sources are in phase, the value o f R for which maximum power is transferred from circuit A to circuit B is - I ! ,----~ 2n - j1 ~3J n L -----+--+-------I___.J,Circuit A (B) 1.4 (A) 0.8 Q Q.30 I' Circuit B . ( D) 2.8 Q (C) 2 Q Q T he state variable description o f an LTI system is given by y=(l oo{::J where y is the output and u is the input. The system is controllable for (A) a 1 :;e 0 , a 2 = 0 , a 3 :;e 0 (C) * 0, a * 0 a 2 * 0, a = 0 ( B) a 1 = 0 , a 2 ,... (D) a 1 :;e 0 , a 1 = 0 , a 2 :;e 0 , a 3 = 0 3 3 T he Fourier transform o f a signal h (t) is H ( j cu) = ( 2cos cu)(sin2 cu) I cu. T he value o f h(O) is (A) 1/4 (B) 1/2 O'J ., (D) 2 (C) 1 T he feedback system shown below oscillates at 2 rad/s when R(s)+~ - s +as 2 +2s+l ( B) K ( D) K , (A) K = 2 and a = 0.75 (C) K = 4 and a = 0.5 Y(s) K ( s + 1) 3 = = 3 and a = 0.75 2 and a = 0 .5 I Q .33 The input x (t) a nd output y (t) o f a s ystem are related as y (t) = Jx( r) cos (3 r) dr . The system is -<XJ (A) time-invariant and stable (C) time-invariant and not stable Q.34 A transmission line with a characteristic impedance o f 100 .Q is used to match a 5 0 Q section to a 200 Q section. I f the matching is to be done both at 429 M Hz a nd 1 GHz, the length o f the transmission line c an b e approximately ~(A) EC-C ( B) s table and not time-invariant ( D) n ot time-invariant and not stable 82.5 e m (B) 1.05 m (C) 1.58 m (D) 1.75 m 7/20 2012 Q .35 ELECTRONICS & COMM N. ENG G. - EC A B PSK s cheme operating o ver a n A W GN c hannel with noise p ower s pectral density o f N 0 /2, u ses equiprobable signals s 1(t)=J sin({l)J) a nd s 2 (t)=-J sin({l)ct) o ver the symbol interval (0, T) . I f the local oscillator in a coherent receiver is ahead in phase by 45 with respect to the received signal, the probability o f e rror in the resulting system is (A) Q .36 Q[~) Q[/f) QU2!,) ( B) 100 -o3] and (C) 10 I=[~ ~], the value of A 3 is T he maximum value o f f (x) = x 3 - 9 x 2 + 2 4x + 5 in the interval [1, 6] is (A) 21 ( B) 25 (C) 41 (A) - 5 V (B) 2 V (C) 3 v (D) 4 6 (D) 6 V T he v oltage gain Av o f the circuit s hown b elow is (A) EC-C ( D) 0 . ( B) 19 A + 30 I ( D) 17 A + 21 I (A) 1 5A+12I (C) 17 A + 15 I Q .40 (D) Q(J !, : 4 G iven that A= [ -5 2 Q.38 (C) T he s ource o f a s ilicon (ni = 10 10 p er c m3) n -channel M OS t ransistor has an area o f 1 sq J..lm and a depth o f 1 J..lm. I f the dopant density in the source is 10 19/cm 3, the number o f h oles in the source region with the above volume is approximately (A) 107 Q.37 ( B) I Avl ~ 200 8/20 2012 Q.41 E LECTRONICS & C OMMN . E NGG.- EC The state transition diagram for the logic circuit shown is Lo Q ~CLK - ~~ 0 2-1 M UX X1. y xo elect S Q - if .I ~ ( B) (A) A=1 A=O (C) - (D) t / L et y [n] d enote the convolution o f h[n] a nd g[n], w here h [n] = ( 1/2)" u[n] a nd g[n] is a causal sequ~nce. I f y[O] = 1 a ndy[ 1] (A) 0 Q.43 \ j\~ ~' A Q.42 r (Q ~ = 1/2, then g [ 1] equals (C) 1 (B) 1/2 ( D) 3/2 T he circuit shown is a c I nput (A) low pass filter with f 3ds +-1 + -l O utput l = ( R 1 +R 2 )C r ad/s (B) high pass filter with f3ds = _ I_ r ad/s RIC (C) low pass filter with f3ds = (D) high pass filter with f3ds EC-C = _ I_ r ad/s R IC 1 ( R 1 + R2 )C rad/s 912 0 2 012 Q .44 ELECTRONICS & COMM N. ENGG. - EC T he m agnetic f ield a long t he p ropagation d irection i nside a r ectangular w aveguide w ith the c rosssection s hown i n t he f igure is H z= 3 c os(2.094 x 10 2 x) c os(2.618 x 10 2 y ) c os(6.283 x 10 10 t- jJz) y 1.2 em 3 cm X T he p hase v elocity v P o f t he w ave i nside t he w aveguide s atisfies - (A) v P > c Q .45 ( B) v P =c ( C) 0 < vP < c T he s ignal m (t) as s hown is a pplied b oth t o a p hase m odulator ( with k P a s t he p hase c onstant) a nd a f requency m odulator ( with k 1 a s t he f requency c onstant) h aving t he s ame c arrier f requency . m t) ( 2 -2 0 2 4 6 8 t (se conds) -2 T he r atio k P j k 1 ( in raci/Hz) for t he s ame m aximum p hase d eviation is ( A) 8 n Q .46 ( B) 4 n ( C) 2 n ( D) n I n t he C MOS c ircuit s hown, e lectron a nd h ole m obilities a re e qual, a nd M1 a nd M 2 a re e qually s ized . T he d evice M 1 is i n t he l inear r egion i f 5V ( A) Y in < 1.875 Y ( B) 1 .875 Y < Yin < 3.125 Y (C) Yin > 3.125Y (D) 0 < Yin < 5 Y Q .47 A b inary s ymmetric c hannel ( BSC) h as a t ransition p robability o f 1/8. I f t he b inary t ransmit s ymbol X is s uch t hat P (X= O) = 9/ 10, t hen t he p robability o f e rror f or a n o ptimum r eceiver w ill b e ( A) 7/ 80 EC-C (B) 63/ 80 ( C) 9/ 10 (D) 1/ 10 I 0 /20 2012 E LECTRONICS & C OMMN. E NGG.- EC Common Data Questions Common Data for Questions 48 and 49: In the three dimensional view o f a s ilicon n-channel M OS t ransistor shown below, 6 = 20 run. The transistor is o f width 1 ~un. T he depletion width f anned at every p-n j unction is 10 n m. The relative permittivities o f Si and S i0 2 , respectively, are 11.7 and 3.9, and c:0 = 8.9 x 10- 12 F/ m. p substrate B Q.48 Q.49 The gate-source overlap capacitance is approximately (B) 0.7 p F (C) 0 .35 fF (A) 0 .7 fF (D) 0.24 p F T he source-body junction capacitance is approximately (A) 2 fF (B) 7 fF (C) 2 pF (D) 7 pF Common Data for Questions 50 and 51: With 10 V de connected at port A in the linear nonreciprocal two-port network s hown b elow, the following were observed: (i) 1 Q c onnected at po1t B draws a current o f 3 A (ii) 2.5 Q c onnected at port B draws a c unent o f 2 A + Q .50 With 10 V de connected at port A, the current drawn by 7 Q c onnected at port B is (A) 3/7 A (B) 517 A (C) 1 A (D) 917 A Q.51 F or the same network, with 6 V de cmmected at port A, 1 Q coru1ected at port B draws 7/3 A. I f 8 V de is connected to port A, the open circuit voltage at port B is (A) 6 V EC-C (B) 7 V (C) 8 v (D) 9 V 11 /2 0 2012 E LECTRONICS & C OMMN. E NGG.- EC Linked Answer Questions Statement for Linked Answer Questions 52 and 53: An infinitely long uniform solid wire o f r adius a c arries a uniform de current o f d ensity ] . Q .52 T he m agnetic field at a distance r f rom the c enter o f t he wire is proportional to (A) r for r < a a nd ( C) r for r < a a nd Q.53 t/ r 1/r 2 ( B) 0 for r < a a nd for r > a 1/r for r > a ( D) 0 for r < a a nd 1 /r 2 f or r > a for r > a A hole o f r adius b (b < a) is n ow d rilled along the length o f the w ire at a d istanced from the center o f the wire as shown below. T he m agnetic field inside the hole is (A) uniform and depends only o n d ( C) uniform and depends on both b a nd d ( B) uniform and depends o nly o n b ( D) non uniform Statement for Linked Answer Questions 54 and 55: T he t ransfer function o f a c ompensator is given as Gc(s)=s+a_ s +b Q .54 Gc(s) is a lead compensator i f ( B) a = 3, b = 2 ( D) a = 3, b = 1 (A) a =l,b=2 ( C) a =-3, b=-l Q .55 T he p hase o f the above lead compensator is m aximum at (A) EC-C . fi rad/s (B) J3 r ad/s (C) J6 rad/s (D) 11 J3 r ad/s 12 /20 2 012 ELECTRONICS & COMMN . ENGG . - EC General Aptitude (GA) Questions (Compulsory) Q. 56 - Q. 60 carry one mark each. Q .56 Choose the most appropriate w ord from the options g1ven below to complete the following sentence: Given the seriousness o f the situation that he had to face, h is_ w as impressive. ( A) b eggary Q.57 (B) nomenclature (C) j ealousy ( D) n onchalance Which one o f the following options is the closest in meaning to the w ord g iven below? Latitude (A) Eligibility Q.58 ( B) F reedom (C) Coercion ( D) M eticulousness O ne o f the parts ( A , B, C , D ) in the sentence given below contains an ERROR. Which one o f the following is INCORRECT? I requested that he should be given the driving test today instead o f tomorrow. (A) requested that (B) should be given (C) the driving test ( D) instead o f t omorrow Q.59 If (l.OOI) 1259 = 3 .52 and ( 1.001) 2062 (A) 2.23 Q.60 ( B) 4.33 = 7.85, then ( l.001i 32 1 = ( C)11.37 ( D) 2 7.64 C hoose the most appropriate alternative from the options given b elow to complete the following sentence: I f the tired.soldier wanted to lie down, h e_ the mattress out on the balcony. (A) should take ( B) shall take (C) should have taken (D) will have taken Q. 61 - Q. 65 carry two marks each. Q .61 T here are eight b ags o f rice looking alike, seven o f w hich have equal weight and one is s lightly heavi e r. T he weighing balance is o f u nlimited capacity. U sing this balance, the minimum number of wei ghings required to identify the heavier b ag is (A) 2 EC-C ( B)3 (C) 4 ( D) 8 13/20 2 012 E LECTRONICS & C OMMN. E NGG.- EC Q .62 T he data given in the following table smmnarizes the monthly b udget o f a n a verage household. A mount ( Rs.) 4 000 1 200 2 000 1 500 1 800 C ategory F ood C lothing R ent S avings O ther e xpenses T he a pproximate percentage o f t he monthly budget N OT s pent o n s avings is ( B) 1 4% ( A) 10% Q.63 (C) 8 1% / (D) 8 6% A and B are friends. T hey d ecide t o m eet b etween 1 P M a nd 2 P M o n a g iven day. T here is a condition that whoever arrives first will not wait for the o ther for more than 15 minutes. T he p robability that they will m eet o n t hat day is ( B) 1/16 ( A) 114 (C) 7116 (D) 9/16 O ne o f the legacies o f t he R oman l egions w as d iscipline. In the legions, military law prevailed and discipline was brutal. Discipline on the battlefield kept units obedient, intact and fighting, even when the odds and conditions were against them. Q.64 W hich one o f the following statements best sums u p t he m eaning o f the above passage? (A) Thorough regimentation w as t he main reason for the efficiency o f the Roman legions even in adverse circumstances. (B) The legions were treated inhumanly as i f t he men w ere a nimals. (C) Discipline was the a rmies' i nheritance from their seniors. (D) The harsh discipline to which the legions were subjected to led to the odds and conditions being against them. Q.65 Raju has 14 currency notes in his pocket consisting o f o nly Rs. 20 n otes and Rs. 10 n otes. T he t otal money value o f the notes is Rs. 2 30. T he n umber o fRs. 10 n otes that R aju has is (B) 6 (A) 5 (C) 9 (D) 10 ~ oB 'V ~ <!"' r/ ~ tf EC-C E ND OF THE QUESTION P APER ' )! /A vY v ;f ......_f:::J ~ ~ \P ~ 14/20

Formatting page ...

cbsinghmb chat

Horizontal lines at:
Guest Horizontal lines at:
AutoRM Data:
Box geometries: