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EC-2009 - INDIAN SPACE RESEARCH ORGANISATION ELECTRONICS...

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Unformatted text preview: INDIAN SPACE RESEARCH ORGANISATION ELECTRONICS AND COMMUNICATION ENGINEERING 1 If a counter having 10 FFs is initially at 0, What count will it hold after 2060 pulses? a) 000 000 1100 b) 000 001 1100 c) 000 001 1000 d) 000 000 1110 2 A memory system of size 16 K bytes is required to be designed using memory chips which have 12 address lines and 4 data lines each. Then the number of such chips required to design the memory system is , a)2 b)4 . c)8 d) 16 3 Consider the following program for 8085 XRA A LXI B, 0007H LOOP : DCX B JNZ LOOP The loop will be executed a) 8 times ' b) once c) 7 times d) infinite times 4 A certain JK FF has tpd=12 ns. The largest MOD counter that can be constructed from such FFs and still operate up to 10 MHz is ' ’ a) 16 b) 256 ‘ c) 8 d) 128 5 Convolution of x(t+5) with impulse function 5(t—7) is equal to a) x(t—2) ‘ b) x(t+12) c) x(t—12) d) x(t+2) 6 The purpose of a Cassegrain feed in a parabolic reflector antenna is to a) Achieve higher antenna gain b) Reduce the antenna size c) Reduce the beamwidth I d) Ease of locating the feed at convenient point Electronics and Communication Engineering SET-A ,___lN,DJANeS;EACE-RESEARCH ORGANISATIONMWW_ ELECTRONICS AND COMMUNICATION ENGINEERING 7 A transfer function G(s) has pole—zero plot as shown in the figure. Given that the steady state function gain is 2, the transfer function G(s) will be given by ' Im 5(s+1) s2 +4s+4 10(s+1) $2+4s+5 8 The im edance of a series RLC circuit is ' 201/1?2 +X2 +Xf b) R2 +X2 —X2 c) 4/132 +(XL +XC)2 (1)1/132 +(XL 4592 9 The advantage of n/4 QPSK compared to conventional QPSK is ? a) 1t/4 QPSK requires less bandwidth compared to conventional QPSK b) 7c/4 QPSK produces lower envelope variation compared to conventional QPSK c) 7t/4 QPSK receiver design is simple compared to conventional QPSK (1) There is no advantage ‘ a) C) 10 A moving coil iron ammeter may be compensated for frequency errors by a) Series inductance Q h) Shunt resistance c) Series resistor. _ ,_ d) Shunt capacitor 11 Find the value of V0 in the figure. a) 1/2 V b) «1/2 V c) 0 V d) on v Electronics and Communication Engineering 12 13 . 1.4. 16 17 18 Electronics and Communication Engineering INDIAN SPACE RESEARCH ORGANISATION -----—-----—-_-—'——.__; " " W " ' ' “ii" " W """“*‘"‘3‘OF 13 ELECTRONICS AND COMMUNICATION ENGINEERING What is the approximate skin depth in copper at 100 MIIZ? a) 0.1 micron b) 10 microns c) 10 mm d) 100 mm While designing a low noise amplifier, what is the importance of the noise resistance of a transistor? ‘ I a) It gives the effective impedance offered by the input with respect to noise current b) It defines the criterion for conjugate matching of input impedance c) It tells us the resistancerthat would generate the same amount of noise at room temperature d) It tells us how rapidly the noise figure increases as we move away from the optimum source impedance Unattenuated radiation field at the surface "of the earth of a quarter-wave monopole will exist if the earth surface is a) Lossy dielectric b) Perfect insulator c) Perfectly conducting (1) None of these Given that 1 O O A = 0 2 O 0 0 3 Evaluate A3 — 6A2 + 11 A — 101 a) Null matrix b) Identity matrix c) 41 d) None of the above lini x log sin(x) is x—>0 a) O ’ b) I/;: c) 1 l d) 2 A 12 bit ADC is operating with a 1 us clock period and the total conversion time is seen to be 14 us. The ADC must be of a) Flash type * i b) Counting type c) Integrating type K d) Successive Approximation type Which of the following types of devices is not field programmable? a) FPGA b) ASIC c) CPLD d) PLD 20 21 22 JED IAIELS, P AC E RESEARC H 0 RGAN l SATIONL'EEA ———----e—-.*-——¥ ELECTRONICS AND COMMUNICATION ENGINEERING Which is the correct order of different process steps for a typical FPGA design? "' a) Functional simulation, Synthesis, Place & Route, Timing Verification b) Functional simulation, Timing Verification, Synthesis, Place & Route c) Timing Verification, Synthesis, Functional simulation, Place & Route d) Synthesis, Functional simulation, Timing Verification, Place & Route The theoretical dividing line between Reduced Instruction Set computing (RISC) microprocessor and Complex Instructions Set Computing (CISC) microprocessor is a) Instruction execution rate to be one instruction per clock cycle b) Number of address and data lines ’ c) "N umber of pins in the chip . A i d) None of the above In a pulsed radar, the peak radar transmitter power is increased by a factor of 81 keeping all other radar parameters unchanged. The maximum range capability of the radar increases by a factor of a) 81 b) 9 c) 27 ' d) 3 A radar transmitter has a PRF of 1500 PPS and a pulse width of 1 micro second. Its duty cycle is a a) 0.0075 b) 0.015 g c)0.6015 . d) 0.00075 23 24 26 Which of the following technology results in least power dissipation ? a) CMOS b) ECL c) TTL d) NMOS A power MOSFET is a q a) Current controlled device b) Frequency controlled device c) Voltage controlled device _ (1) None of the above The advantage of differential PSK (DPSK) over coherent PSK is a) DPSK requires less bandwidth compared coherent PSK b) DPSK receiver design is simple compared to coherent PSK c) DPSK Bit Error rate is lower than coherent I’SK — d) For same bandwidth, DPSK bit rate is higher compared to coherent PSK An ideal current meter should have a) Zero resistance V - b) Finite resistance c) Infinite resistance ' (1) Very large resistance Electronics and Communication Engineering . INDIAN SPACE RESEARCH ORGANISATION — ..... E ,, WW..- __,,‘__ n.i-__,..__ .1" 7, ' t m. _.,,,AA,,A__*__5~OF 13 ELECTRONICS AND COMMUNICATION ENGINEERING 27 For the network shown in the figure Vi(t) is the input and i(t) is the output. The transfer function R L . [(5) p ‘ M {5(3) 4 Vim 7 1m _ c of'the network is i‘—E_J a) C ' “ ' " b) C RCS2+LCS+1 ’ ’ LC52+RCS+1 c)‘ ”(is h i d) Cs - RCs2 +LCS +1 LCS2+RCS+1 28 The length of a lossy shorted stub is 1/32 A. What will be the nature of its input impedance? a) A low inductive reactance in series with a low resistance b) A low capacitive reactance in shunt with a high resistance c) A high capacitive reactance in series with a low resistance d) A high inductive reactance in series with a low resistance 29 Refer to the circuit in the figure. Which of the following statements is NOT true about 200' Ohm this circuit? V Vin WWW ‘10 Ohm a) It is a low pass filter b) It has a finite attenuation at infinite frequency c) Its phase shift varies monotonically with d) It has one pole and one zero the frequency Electronics and Communication Engineering 30 Which of the following is the correct continuity equation: a a ) v . J :13 at c)VoJ:0 b ) V. :—a—’0 ' a: d) v. =_3_E a: 31 0L,B are the roots of the equation x2 + x + 1 = 0. Then 03“ +B3" is a) 1 b)2 c)0 32 A point moving in the complex plane satisfies the following relation z2 + 2*2 = 8, where 2* stands for the complex conjugate of z. d)3 - The difference of the distances of the moving point from (2‘12;0) and Gib/2,0) is a)8 b)2 c)4 d)6 33 The greatest negative number which can be stored in a computer that has 8—bit word length and uses 2’s complement arithmetic is a) -256 b) -255 c) -128 34 _ Which of the following ADCS uses over sampling in its operation a) Sigma — delta ADC c) Successive Approximation Register ADC 35 A mealy state machine’s output depends on a) State and outputs c) State d) -127 b) Counter ramp convertor d) Flash Convertor 1)) Inputs d) State and inputs 36 The charlicteristic equation of the T-FF is given by ’3) Q+=TQ C)Q+=TQ b>Q*=TQ _ d)Q+=TQ+QT 37 Percentage modulation of an AM wave having a power content of 8 KW at carrier frequency and 2 KW in each of its side bands is a) 60 % ' b) 70 % c)100 % d) 80 % ‘38 Approximate equivalent noise temperature (deg. K) of an amplifier with a noise factor of 1.04 is . a) 301.6 b) 11.6 39 A differential amplifier is used in the input stage of Op-Amps to achieve very high a) open —loop gain b) bandwidth Electronics and Communication Engineering . c) 278.4 c) slew rate d) 5.8 d) CMRR S ET-A ELECTRONICS AND COMMUNICATION ENGINEERING 40 Which two-port parameters are best suited for analyzing a series-shunt feedback circuit? a) Z—Parameters b) H—Parameters c) Y—Parameters d) S-Parameters 41 8 i=0 30 For the circuit shown in the figure, the switch is closed at 1:0. After some time when the current in the inductor was 6A, the rate of change of current through the inductor was ALA/sec. The value of the inductor is a) 0.5 H b) 1.5 H r c) 1.0 H d) Indeterminate 42 120K Q KM 2V Hm V0 In the circuit shown in the above figure, the value of output V0 is a) +6V V » b) -9v ' c) -6V (1) +9v Electronics and Communication Engineering ELECTRONICS AND COMMUNICATION ENGINEERING 43 The characteristics equation of a closed loop control system is given as $2 + 4S +16 2’0 . The resonant frequency in radian/sec of the system is a) 2 b) zfi c) 4 d) 2J5 44 Which point in the Smith Chart is labeled with the WRONG impedance? ~“.k’-~.2£}J..f’2 i 5:? a) 10+j10 b) 50+j50 c) 200-j200 d) 25-j50 45 If a line is terminated in an open circuit, the VSWR is a) 00 V b) 0 c) 1 d) —1 46 Unit of relative permeability is a) Henry/meter b) Henry c) Henry—meter d) It is dimensionless 47 f(x) = [tanzx] ( stands for greatest integer function) a) f(x) continuous at x = 0 b) limit f(x) does not exist as X tend to 0 c) f(0) = 1 d) {(11) not derivable at x = 0 48 Number of real values of (a +ib)““ + (a—ib) 1/“ is a) 0 b) 1 c) n d) None of the above Electronics and Communication Engineering ELECTRONICS AND COMMUNICATION ENGINEERING 49 A 5 bit DAC has a current output. For a digital input of 10100, an output current of 10 mA is produced. What will be the output current for a digital input of 11101? a) 14.5 mA b) = 10 mA c) = 100 mA d) Not possible to calculate 50 The ethernet protocol uses a) CSMA/CA b) SCPC‘ 7 c) CSMA/CD ‘ d) Slotted ALOHA 51 A micro controller differsfrom a microprocessor in terms of a) 1/0 interfaces and instruction decoding b) Memory configuration and I/O interfaces c) Data bus width and clock speed i d) Memory configuration and instruction decoding 52 An 8-bit microcontroller has an external RAM with the memory map from 800011 to 9FFFH. The number of bytes this RAM can store is a) 8193 b) 8192 , c) 8191 - d) 8000 53 An audio frequency of 15 KHz is frequency modulated with a deviation of 75 KHz. The resulting bandwidth is a) 180 KHZ b) 150 KHz ' ‘ c) 210 KHz (1)240 KHz 54 A IkW carrier is Amplitude Modulated to a depth of 60%. The total power in the modulated carrier is a) 1 kW b) 1.06 kW c) 1.6 kW ‘ d) 1.18 kW 55 V 39 WW" The yu parameter of the network shown in the given figure will be a) % 18% c) 1 d)-% Electronics and Communication Engineering ELECTRONICS AND COMMUNICATION ENGINEERING 56 An inductance of 1 H is realized using air core with 100 turns. What will be the inductance if the number of turns are doubled ? a) l H b) 0.5 H c) 2 H d) None of these 57 An inductor of inductance 0.1 H, carrying current of *6 Amps vvill store energy of a) 6 Joules b) 36 Joules ' c) 1.8 Joules d) 3.6 Joules 58 A coil has self resistance of SQ and inductance of 1 pH. The value of Q at 1 MHz frequency is - a) 200 b) 100 c) 40 d) None of these 59 The closed loop transfer function of a unity feedback control system is G(s) = ———2 . The closed loop transfer function will have poles at (S + 2) a) —2, ij . b) —2,—1 c) an d) -2,2 60 The dominant mode of propagation in microstrip line in low frequency approximation is a) TM“ b) Quasi-TEM c) TEM d) TEOI 61 Consider a transmission line of characteristic impedance 50 ohms and the line is terminated at one end by +j50 ohms, the VSWR produced in the transmission line will be a) +1 b) zero c) —1 ’ d) infinity 62 The divergence of magnetic flux density is a) j , b) P C) 0 d) 00 63 A straight line and a circle of radius a are given. A chord is drawn at random to this circle parallel to the given line. Expected length of the chord is a) 2a I b) 712a ‘ c) na/Z , (1) None of the above 64 There is a function f(x), such that f(0) = 1 and F(0)= -1 and f(x) is positive for all values of x. Then, a) P'(x) <0 for all xv b) —1 < f" (x) < 0 for all x c) —2<t“ (x)<-1 for allx ' (1) None of the above Electronics and Communication Engineering 65 66 67 68 69. 70 71 INDIAN SPACE RESEARCH ORGANISATION 777777 V f —:~~ ~ ~~w-~~»~r~————1~1 OF 13 ELECTRONICS AND COMMUNICATION ENGINEERING Interrupt latency is the time elapsed between: a) Occurrence of an interrupt and its detection byithe CPU b) Assertion of an interrupt and the start of the associated ISR c) Assertion of an interrupt and the completion of the associated ISR d) Start and completion of associated ISR Inverse Fourier transform of signal I X(j oa)=27c5(co) + 7:5(03 - 41c) + 1:8(03+47r) a) 1+cos47ct b) at(1—cos41ct) c) 27t(1-cos41:t) d) 27t(1+COS4Ttt) Determine the discrete-time Fourier Transform for the signal xin1=[—z, ~15 0, 1., 2] - i_t._. n=0 a) 2j(2sin 20) + sin 0)) b) -2j(Zsin 203 + sin 0)) c) 2(2cos 20) — cos 0)) d) -2(2cos 203 - cos (:3) Auto-correlation of a sinusoid s(t)=A sin(cot) is a) (AZ/2) sin((m:) b) (A/2) sin(cor) c) (AZ/2) cos(m) d) (A/2) cos(03'c) A source produces 4 symbols with probabilities 1/2,1/4,1/8,1/8. For this source, a practical coding scheme has an average codeword length of 2 bits/symbol. The efficiency of the code is a) 1 b) 7/8 c) 1/2 d) 1/4 When signal frequency is 2000 KHz and IF is 455 KHz, the image frequency could be a) 2910 KHz . b) 1645 KHz c) 2455 KHz d) 2090 KHz The Q of RLC tuned circuit with source voltage V in the figure is 100 at resonant frequency of 100 KHZ. . R L C What is the voltage VL “VA/\Nme——l F‘ across inductor at resonance ? a) 50V to) VL— VC c) 100V d) VR— VC Electronics and Communication Engineering SET-A 12 OF 13 72 A 5V reference is drawn from RS T“ the circuit shown in the figure. 10V . n f 53; Zener diode of 400mW and 5V, W ' with firing current of SmA is used. The value of Rs is 5mg 95m A a) 50 ohms b) 500 ohms c) 75 ohms d) 470 ohms 73 Find the equiValent resistance a 200 Q. R for the network shown in the figure. 200 Q R E: 200 Q 100 Q a) 200 ohms b) 101 ohms c) 220 ohms d) 100 ohms ‘ 74 n The Voltage across last resistor is V. All resistors are unity. Then Vs is given by a) 13 V b) 8 V , c) 4- V d) None of these ' 75 Natural frequency of a unity feedback control system of transfer function - 10 G(s) = —-— is 5(3 + 1) a) 0.5 rad/sec h) 3.16 rad/sec c) 4.6 rad/sec ‘ d) None of these Electronics and Communication Engineering 76 77 78 79 80 ELECTRONICS AND COMMUNICATION ENGINEERING Which of the following conditions will not guarantee a distortionless transmission line? a) R = 0, G = 0 b) Very low frequeney range (R >> 03L, G >> 60C) c) R/L = G/C. ' (1) Very high frequency range (R << 03L, G << 03C). For a line of characteristic impedance Z0 terminated in a load ZR such that ZR> Z0, the Voltage Standing Wave Ratio (V SWR) is given by a) ZR/Zo b) Z0 C) ZR d) 20/ ZR The beamwidth of a reflector antenna of diameter = 70 cm at 30 GHz is a) 3.7 degree b) 0.5 degree .2, c) 1.1 degree d) 1 degree Tr = r/(1+ r2+ r4) 2: = 1 a) 1A . b) 1 c) None of the above d) 1/2 A man with n keys wants to open a lock. He tries his keys at random. The expectednumber of attempts for his success is (keys are replaced after every attempt) a) {1/2 b) n c) ‘In _ d) None of the above Electronics and Communication Engineering ...
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