ies obj electronics &telecomm.ii 2004 (www.egate.ws)

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PAPER II

1.

The root loci of a feedback control systemfor large values of s are asymptotic to thestraight lines with angles 0 to the real axisgiven by which one of the following?(Where p = Number of finite poles ofG(s)H(s), z = Number of finite zeros ofG(s) H(s) and k = 0, 1, 2, ..)

a.

2 1

p z

k

b. 2 1

1

k

p

c. 2k p z

d.2k

zp

2. The forward path transfer function of a

unity feedback system is given by

2100

10 100G s

s s

The frequency response of this system willexhibit the resonance peak ata. 10 rad/s

b. 8.66 rad/s

c.

7.07 rad/sd. 5 rad/s

3.

Consider the following Nyquist plot

With which one of the following transfer

functions, does the above Nyquist plotmatch?

a.

3

1

1s

b.

2

1

1s

c. 2

1

2 2s s

d.

1

1s

4. The forward path transfer function of a

unity feedback system is given

by 2

1

1G s

s

. What is the phase

margin for this system?

a.

- radb.

0 rad

c. /2 rad

d. rad

5.

All the constant N-circles in G-planescross the real axis at me fixed points.Which are these points?a.

-1 and originb.

origin and + 1c. - 0.5 and + 0.5d.

- 1 and + 16. What is the value of M for the constant M

circle represented by the equation8x2+ 18x + 8y2+ 9 = 0, where

Re | |x G j and Im | |y G j ?

a.

0.5b. 2c.

3d. 8

7. Which one of the following statements iscorrect?A plant is controlled by a proportionalcontroller. If a time delay element isintroduced in the loop, itsa.

phase margin remains the sameb.

phase margin increases

c.

phase margin decreasesd. gin margin increases8.

Which one of the following statements iscorrect?The effects of phase lead compensator ongain cross-over frequency (cg) and thebandwidth (BW) are,a. that both are decreased

b.

that cg is decreased but BW isincreased

ELECTRONICS TELECOMMUNICATION ENGINEERING

I.E.S. (OBJ) - 2004

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2 of 15c.

that cg is increased but BW isdecreased

d. that both are increased9. How does cascading an integral controller

in the forward path of a control systemaffect the relative stability (RS) and thesteady-state error (SSE) of that system?

a.

Both are increasedb. RS is reduced but SSE is increasedc. RS is increased but SSE is reducedd. Both are reduced

10. Consider the following statements forphase-lead compensation1. Phase-lead compensation shifts the

gain cross-over frequency to the right.2. The maximum phase-lead angle occurs

at the arithmetic mean of the cornerfrequencies of the phase-lead network.

3.

Phase-lead compensation is effectivewhen the slope of the uncompensatedsystem near the gain cross-over is low.

Which of the statements given above arecorrect?a.

1, 2 and 3b. 1 and 2c. 2 and 3d.

1 and 311. A ternary source produces alphabets A, B

and C with probabilities pA = pB= p andpc. Which one of the following gives the

correct values for the maximum value ofthe entropy of the source; and thecorresponding value of p and the range of

p?a.

1.58, 0.33, (0, 0.5)b. 1.0, 0.5, (0, 1)c.

3.0, 0.67, (0, 0.5)d. 2.0, 4.2, (0, 0.3)

12.

In a BPSK signal detector, the localoscillator has a fixed phase error of 20.By what factor does this phase error

deteriorate the SNR at the output?a.

cos220b.

cos 20c. cos 40d.

cos 7013. Which one of the following is represented

by

6 3 65 cos 10 sin 10 sin 10v t t t t

a.

SSB under sideband signalb. DSB suppressed carrier signal

c.

AM signald.

Narrow band FM signal14. Which one of the following statements is

correct? In a radio detectora. linearity is worse than that of a phase

discriminatorb.

stabilization is provided against signal

strength variationsc. the output is twice of that obtainablefrom a similar phase discriminator

d. the circuit is same as that in adiscriminator, except that the diodeconnections are reversed

15. Consider minimum shift keying (MSK)also known as last FSK with frequencyspacing 2 fdbetween the state frequencies.rb is the data rate. Which one of thefollowing correctly relates rband fd?

a. / 4d bf r

b. / 2d bf r

c. 3 / 4

d bf r

d. d bf r

16.

In a broadcast transmitter, the RF output isrepresented as

50 1 0.89cos5000 0.30sin9000e t t t

10cos 6 10 t voltWhat is the SNR improvement with FSKover ASK in most types of noise

environment?a. 200 to 300 dBb. 3 to 4 dBc. 10 to 12 dBd.

0 dB17. What is the SNR improvement with FSK

over ASK in most types of noiseenvironment?a. 200 to 300 dBb. 3 to 4 dBc. 10 to 12 dB

d.

0 dB18.

The sum of two signals

31 3sin 4 10e t and

2 5sin 2 256e t is sampled at 1024

Hz. The sampled signal is passed througha low pass filter with cut off at 2048 Hz.The output of this filter will containcomponents ata. 256 Hz and 103Hzb.

256 Hz and 1024 Hz

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3 of 15c.

256 Hz onlyd.

1024 Hz only19. Consider the following circuit of a

scrambler:

X p input data stream polynomial

Y p output data stream polynomial

' s shift-register stages

's OXR gatesWhich one of the following relates X(p)and Y(p)?

a. 4 3/ 1Y p X p p p

b. 4 4 3/ 1Y p p X p p p

c.

4/ 1Y p X p p p

d. 4 4/ 1Y p p X p p p

20. A filter at the input to a processing systemis shown in the diagram given below:

The channel works for toll qualitytelephone use. If the filter He(S) is to bedesigned so that linear distortion is

minimized, then He(S) should have whichone of the following?a. Constant delay

b. Constant phasec. Inverse relationship with H(s)d. Inverse relationship with H(s) and

constant delay21.

What is the responsivity of a photodiodehaving a quantum efficiency of 65% with

photons of energy 1.5 10-19 J incidentupon it?

a.

1

0.832AW

b. 10.714AW

c. 10.694AW

d. 10.452AW

22. The normalized frequency of a step indexfibre is 28 at 1300 nm wavelength. What isthe total number (approximately) of guidedmodes that can be supported by the fibre?a.

50b. 200

c.

400d.

80023. What is the beam width of a pyramidal

horn antenna with aperture dimension of 9cm 8 cm and operating at a frequency of5 GHz?a.

7.2

b.

10c. 15d. 16.4

24. Match List I (Designation of RadarFrequencies) with List II (Frequency.Range) and select the correct answer:List IA.

SB. XC. KuD. K

List II1.

18 - 26.5 GHz2. 2 - 4 GHz3. 8 - 12.4 GHz4. 12.4 - 18 GHzCodes;

A B C Da. 1 3 2 4b. 1 4 2 3c. 2 3 1 4d. 2 4 1 3

25.

Which one of the following statements iscorrect?Microwave link repeaters are typically 50km aparta. because of atmospheric attenuationb. because of output tube power

limitationsc. because of earths curvatured.

to ensure that the applied d.c. voltageis not excessive

26. Match List I with List II and select thecorrect answer using the codes given

belowList IA.

Deviative absorptionB.Non-deviative absorptionC. Atmospheric noiseD.

Unabsorbed field strengthList II1.

Depends on thunderstorms

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4 of 152.

Depends on the region of theionosphere where the wave is bent

back to earth3. Depends on D-layer region where the

collision frequency is high4. Is less than inverse distance attenuationCodes;

A B C Da. 2 4 1 3b. 2 3 1 4c. 1 4 2 3d.

1 3 2 427. Consider the following statement

Electromagnetic waves are refracted whenthey1. pass through a medium of different

permittivity2. pass through a small slot in a dielectric

slab3.

are incident on a perfectly conductingsurface

Which of the statements given above is/arecorrect?a.

1 onlyb. 2 onlyc. 3 onlyd. 1 and 3

28. In parametric amplifiers used inmicrowave communication systems, the

pump energy mainly restricts which one of

the following?a. Bandwidth

b. Gainc.

Noise leveld. Operating frequency

29.

Which one of the following techniques isnot suitable for automatic satellitetracking?a.

Monopuleb. Step-trackc. Conical scanning

d.

Lobe switching30. What is the octal equivalent of decimal

0.3125?a. 0.42

b.

0.3125c. 0.24d. 0.12

31. How many ls are present in the binaryrepresentation of

4 4096 9 256 7 16 5 ?

a.

8b.

9c. 10d.

1132. Given three integer variables a, b, c where

each one will take positive value. Whichone of the following expressions in C

avoids overflow?a. a + b + cb. b + a cc. b c + ad.

c + a + b c c33. x.: = 1; y: = 0;

while y < k dobeginx: = 2 * x;y : y + 1end;

For the above Pascal program fragmentinvolving integers x, y, and k, which oneof the following is a loop invariant; i.e.true at the beginning of each execution ofthe loop and at the completion of the loop?a.

x = 2yb.

x = y +1c. x = (y + 1)2d. x = (y + 1)2y

34. Consider the following C program;main( ){pri ( ); pri ( ); pari ( )}pri ( ){

static int k;print {%d, ++k);}Which one of the following is correct inrespect of the program given above?a.

It prints 012b. It prints 123c.

It prints 111d.

It prints 3 consecutive butunpredictable numbers

35. Consider a complete graph with n vertices.What is the total number of spanningtrees?

a. 1

2

n n

b. 2n 1c. n!

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5 of 15d.

n n - 236.

It is given that two pointer variables p andq are of the same type and p < q. Whichone of the following operations is logicallynot correct?a. p - q

b.

p + q

c.

p + 5d. p ++37. Match List I (Type of Data Structure) with

List II (Used in Application ) and selectthe correct answer:List IA. StackB.

TreeC. RecordD. ArrayList II

1.

Solving linear simultaneous equation2.

Subroutine linkage3. File processingCodes;

A B C Da. 3 4 2 1

b. 2 1 3 4c. 2 4 3 1d. 3 1 2 4

38. Which one of the following is not a correctreason for biasing the laser near but belowthreshold in the off state for a laser drivecircuit?a. It reduces the switch-on delay

b.

It allows easy compensation forchanges in ambient temperature

c. It eliminates the spontaneous emissionof light in the off state

d. It reduces the junction heating causedby the digital drive current

39. Which one of the following statements iscorrect? The modal noise in multimodefibres cannot be reduced by

a.

use of a broad spectrum sourceb. using fibres having large numerical

aperturesc. phase correlation between the modesd.

use of a single mode fibre40.

What should be the frequencies used forcommunication inside the coal mines,from the viewpoint of minimizing the

propagation path loss?a. In the range from 30 MHz to 400 MHz

b. En the range from 1 GHz to 4 GHz

c.

In the range from 500 MHz to 1 GHzd.

In the range from 1 GHz to 2 GHz41. Which one of the following statements is

correct?Digital modulation techniques are used insatellite communication systems sincea. they are easier to handle

b.

large bandwidth utilization is possiblec. they have a higher spectral efficiencyd.

they are less prone to interference42.

Which one of the following statements isnot correct?a. A geo-synchronous satellite remains

practically stationary relative to earthantennas

b. A geo-synchronous satellite means thesame thing as geo-stationary satellite

c. There is a trade-off between the cost ofa communication satellite and cost ofits earth stations

d. Three geo-synchronous satellitescannot give 100% global coverage

43. Consider the following statementsA traveling wave tube is a1. broad-band amplifier2.

Linear beam amplifier3. crossed field amplifier4. solid-state amplifierWhich of the statements given above recorrect?

a.

1 and 2b. 2 and 4c.

2 and 3d.

1, 3 and 444. In a Ga As gunn diode the drift velocity is

107cm/s and active region length is 10-3cm. What is the natural frequency ofoscillation?a.

8 GHzb. 9 GHzc. 10 GHz

d.

11 GHz45. Consider the following pairs:

1.

Travelling wavetube: Linear electronbeam

2.

Cavity Magnetron: Strapping3.

Amplitron: CFAWhich of the pairs given above arecorrectly matched?a. 1, 2 and 3b. 1 and 2c.

2 and 3

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6 of 15d.

1 and 346.

A rectangular waveguide operating in thedominant mode is gradually deformed intocircular cross-section in the direction of

propagation. What is the mode at theoutput?a. TM11

b.

TE11c. TE01d. TM01

47. A mode filter has the structure of thinradial wires in a circular waveguide asshown in the diagram given below:

Which one of the following modes isfiltered out by the above mode filter?a. TE01

b. TM01c. TE11d. TM11

48. A 4-port microwave passive device hasscattering matrix of the form

0 0

0 0

0 00 0

p jq

p jq

jq pjq p

Which one of the following statements iscorrect?The device is aa. Hybrid Tee

b.

Hybrid ringc.

H-port circulatord.

Directional coupler

49.

It is given that the first roots of 1 0J x

and 1 ' 0J x

are 3.83 and 1.84respectively. Which one of the followinggives the cut off wavelength of TM11modein a circular waveguide of diameter D?

a. 0.64c D

b.

0.82c D

c. c D

d.

1.2c D

50.

A 50 ohm coaxial line is connected to a 72ohm load through a 60 ohm coaxial section

of length 7.5 mm. What is the inputVSWR on the line if it is fed by a 20 GHzsource?a. 1.0b.

1.25c.

1.33d.

1.44

51.

Match List I with List II and select thecorrect answer using the codes givenbelowList IA. Helical antennasB. DipoleC. Parabolic dishD.

Array antennasList II1. Isotropic radiator2. Circularly polarized radiation

3.

Shaped beams4.

Satellite communication systemsCodes;

A B C Da. 1 2 4 3b. 1 2 3 4c. 2 1 4 3d. 2 1 3 4

52.

Match List I with List II and select thecorrect answer using the codes givenbelow:

List IA. Cavity wave meterB. Magic TeeC. VSWRD. BolometerList II1.

Microwave component2. Microwave power measurement3. Microwave frequency measurement4. Reflection coefficient measurementCodes;

A B C Da. 1 2 4 3b.

1 2 3 4c. 2 1 4 3d. 2 1 3 4

53. Two one-port cavity resonators havingcoupling coefficients K1 and K2 andidentical resonant frequency 0 produceidentical VSWR when used as terminatingloads of waveguide. Which one of the

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7 of 15following relations is satisfied by K1 andK2?

a. 1 2K 0K

b. 1 2 0K K

c. 1 2 1/ 2K K

d. 1 2 1K K

54.

Consider the following circuits:

Which one of the following statements iscorrect?a. Circuit 1 is parallel connection and

Circuit 2 is Darlington connectionb. Circuit 1 is cascade connection and

Circuit 2 is Darlington connectionc. Circuit 1 is Darlington connection and

Circuit 2 is cascade connection

d.

Circuit 1 is cascade connection an&Circuit 2 is parallel connection

55. An amplifier has a d.c. power supply of 15V and draws a current of 10 mA. It

produces an output of 5 V peak across aload resistance of 600 for a signalfrequency of 1 kHz. What will be its a.c.

power output?a. 260 mW

b. 20.8 mWc. 520 mW

d.

40.6 mW56. The transfer function of a transistor

amplifier is given by

0

5 6

4240

1 14 10 4 10

v

s

VA

f fVj j

Which one of the following gives the

approximate upper 3-dB frequency *H

f of

the amplifier?

a.

54 10 Hz

b. 62.2 10 Hz

c. 64 10 Hz

d. 64.4 10 Hz 57. Which one of the following is a wide-band

amplifier?a. RF amplifierb. IF amplifier

c.

Video amplifierd.

AF amplifier58. Consider the following statements:

In JFET amplifiers, high frequencyresponse can be improved by usingpeaking circuits containing inductors1.

in series with drain resistanceR02. in series with the coupling capacitance.3. as a feedback element between drain

and gate.Which of the statements given above are

correct?a.

1 and 2b. 2 and 3c.

1 and 3d. 1, 2 and 3

59. Which one of the following statements iscorrect?If in a double-tuned voltage amplifier, themutually coupled secondary and primaryare synchronously tuned with equal Q-values then for the over-coupled case the

maximum voltage amplificationa. is greater than that for critical couplingand the amplifier characteristic isdouble peaked

b. is less than that for critical couplingand the amplifier characteristic has asingle peak

c. is same as that for critical coupling andthe amplifier characteristic is doublepeaked

d. is less than that for critical couplingand the amplifier characteristic is

doubled peaked60.

A tuned amplifier has a voltage gain of100 and a band width of 10 kHz at 500kHz. It is required to increase thebandwidth to 20 kHz. This can beachieved by which one of the followingways?a. By doubling the gainb.

By doubling the resonant frequencyc. By halving the Q of the coild. By halving the power supply voltage

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8 of 1561.

A d.c. to d.c. converter has an efficiency of80% and is supplying a load of 24 W at240 V. What is the current drawn from the

battery if the converter is working from abattery of 12 V?a. 0.1 A

b. 2.0 A

c.

2.5 Ad. 10 A62. Consider the following circuit:

What is the function of diode D2 in theabove circuit?

a.

To avoid saturation of the Op-Ampb. To provide negative feedback when the

input is negativec. To reduce reverse breakdown voltage

of D1d. As a buffer

63. Consider the following circuit:

Which on of the following expressions for

0V is correct?

a. 1 201 2

z

R RV V

R R R

b. 0 zV AV

c. 102

1zR

V VR

d.

1 20

1 2

z

R RV AV

R R R

64.

Which one of the following statements isnot correct in respect of a series transistorfeedback voltage regulator?a.

The regulation factor can be improvedby increasing the hfe of the shunttransistor

b. The regulation factor can be improvedby increasing the resistance between

the collector of the shunt transistor andthe collector of the series, transistor

c. Output resistance can be reduced byusing a Darlington pair in place of theseries transistor

d. Output resistance can be reduced byreducing the hfeof the shunt transistor

65.

Consider the following Op-Amp circuit

What is the output voltage Voin the aboveOp-Amp circuit?a.

+ 10 Vb.

10 Vc.

+ 11 Vd. 11 V


What is the value of R4 in the abovecircuit, if the voltage V-and V+ are to beamplified by the same amplificationfactor?

a. 7 k

b.

22 k

c. 33 k

d. 35 k67.

What is the load current IL in the abovecircuit?a.

5 mA

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9 of 15b.

10 mAc.

+ 25 mAd. + 50 mA

68.

A 50 Hz symmetric square wave is appliedto the RC-circuit shown in the diagramgiven below.

Which one of the following is the correctshape of the output waveform?a.

b.

c.

d.


For the circuit shown above, which one ofthe following is a correct statement?a. D2 does not conduct for any value of

Vib.

vo10 V for all values of vi> 10 Vc.

vo= 0 V for all values of vi< 0 Vd.

vo= 10 V for all values of vi> 0 V70.

What is the depth of a complete binary treewith n nodes?

a. 2log 1 1n

b. 2log 1 1n

c. 2log 1n

d. 2log 1n

71. A disc drive has an average seek time of10 ms, 32 sectors on each track and 512bytes per sector. If the average time to read

8 kbytes of continuously stored data is 20ms, what is the rotational speed of the discdrive?a. 3600 rpmb. 6000 rpmc.

3000 rpmd.

2400 rpm72.

Given a 32-bit processor with 16 MB mainmemory, 32 kB 4-way set-associative on-chip cache and a cache block size (or linesize) of 16 words. What is the total number

of tag bits in the memory address format?a. 9b. 20c. 11d. 24

73. Match List I with List II and select thecorrect answer:List I (Characteristic)A.

Micro-code for several instructionsB. Lack of indirect addressingC.

Presence of on-chip cache

D.

Simple optimizing compilerList II (Processor Architecture)1.

Both RISC and CISC2. CISC only3.

Neither RISC nor CISC4. RISC onlyCodes;

A B C Da. 2 4 1 3b. 1 3 2 4c. 2 3 1 4

d.

1 4 2 374.

A disc drive has a rotational speed of 3600rpm, an average seek time of 10 ms, 64sectors per track and 512 bytes of data persector: What is the average time to accessthe entire data, of a 16 kbytes file storedsequentially on the disk?a. 18.85 msb. 10 msc. 27.15 msd.

9 ms

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10 of 1575.

A particular parallel program computationrequires 100 seconds when executed on asingle processors If 40 percent of thiscomputation is inherently sequential,then what are the theoretically best elapsedtimes for this program running with 2 and4 processors, respectively?a. 20 and 10 seconds

b.

30 and 15 secondsc.

50 and 25 secondsd. 70 and 55 seconds

76. Consider the following statements

The advantage of cycle stealing in DMA isthat1. it increases the maximum I/O transfer

rate2. it reduces the interference by the DMA

controller in the CPUs memory access3.

it is beneficially employed for I/Odevices with shorter bursts of datatransfer


1 and 2b. 1 and 3c.

2 and 3d. 1, 2 and 3

77. Consider a hypothetical processor withlargest instruction length being 32-bit and16 registers R0 - R15. Processor supports

only following instructionsADD Ri, RjSUB Ri, RjAND Ri, Rj

NOT RiMOV Ri, RjLOAD Address // Loads with

register R0STORE Address // Stores the

content of R0JUMP Address

J Z AddressWhat is the maximum number of address

pins on this processor?a.

27b. 28c. 29d. 30

78. Consider the following statements :The 8085 microprocessor will not enterinto bus idle machine cycle whenever1. INTR interrupts is recognized

2.

RST x.5 is recognized3.

DAD rp instruction is executedWhich of the statements given above is/arecorrect?a. 1 onlyb.

2 onlyc. 1 and 2

d.

2 and 379. Consider the following program:

ORG 7000 HBEGIN: LXI H, 7000 H

MOVE A,LADD HJM ENDRST 0

ENDS: PCHLHLT

Which one of the following statements is correct?

a.

The program will halt the processorb. The program will be repeated infinitelyc. The program will branch to 0007 H

after JM ENDd. The program will branch to 0000 H

after JM END80.

Consider the following program intendedto transfer a block of 5 bytes from A000Hto 9000HSTART: LXI B, 9000 H

LXI H, A000H

MVI C, 05HLOOP: MOV A, MSTAX BINX BINX HDCR CJNZ LOOPHLT

The above program will not work becausea. C Register is used as counterb.

OCR C instruction will not affect zero

flagc. JNZ instruction is used instead of JZd.

The first two instructions in loopshould have been LDAX D and MOVM, A

81. Which is the most common antenna toobtain a predetermined, radiation pattern?a. Array antennab. Corner reflectorc. Sectoral hornd. Helical antenna

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11 of 1582.

Assertion (A): In a transistor switchingcircuit, it is desirable that the transistorshould not be driven into hard saturationfor fast switching applications.Reason (R): When a transistor is undersaturation state, both its emitter-base andcollector-base junctions remain underforward bias.a.

Both A and R are individually true andR is the correct explanation of A

b. Both A and R are individually true butis not the correct explanation of A

c.

A is true but R is falsed. A is false but R is true

83. Assertion (A): In the error detectorconfiguration using a synchro transmitterand synchro control transformer, the latteris connected to the error amplifier.Reason (R): Synchro control transformer

has almost a uniform reluctance pathbetween the rotor and the statora. Both A and R are individually true and

R is the correct explanation of Ab. Both A and R are individually true but

is not the correct explanation of Ac. A is true but R is falsed.

A is false but R is true84. Assertion (A): The error detector in a

position control system using synchropairs employs synchro transmitter for

reference signal and synchro controltransformer for the feedback signal.Reason (R): Synchro control transformerrotor has a uniform magnetic reluctance.a. Both A and R are individually true and


is not the correct explanation of Ac. A is true but R is falsed. A is false but R is true

85.

Assertion (A): The number of branches ofroot locus terminating on infinity is equalto the number of open loop poles minusthe number of zeros.Reason (R): Segment of the real axishaving an odd number of real axis openloop poles plus zeros to their right are

parts of the root locus:a.


b.

Both A and R are individually true butis not the correct explanation of A

c. A is true but R is false

d.

A is false but R is true86.

Assertion (A): The bandwidth of a controlsystem indicates the noise filteringcharacteristic of the system.Reason (R): The bandwidth is a measureof ability of a control system to reproducethe input signal.

a.

Both A and R are individually true andR is the correct explanation of Ab.


c. A is true but R is falsed. A is false but R is true

87. Assertion (A): AM stereo broadcastinguses quadrature carrier multiplexing(QAM)Reason (R): QAM involves more stringentsynchronization than an FDM system withSSB sub-carrier modulation.

a.


b.


c.

A is true but R is falsed. A is false but R is true

88. Assertion (A): Juxtapaposition or bit-

stuffing is encountered in asynchronousmultiplexing.Reason (R): The data rate at the output of acoaxial line change because of the change

in the velocity of the propagating wave.a. Both A and R are individually true and



89. Assertion (A): For a slow wave structure,helix is a broadband lowpower devicewhile coupledcavity chain is a narrowband high-power device.

Reason (R): A helix is a good dissipator ofpower, while a coupled cavity structure ispoor for high power dissipation.a. Both A and R are individually true and



90.

Assertion (A): In free-space transmissionbetween a transmitting and a receiving

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12 of 15antenna, a high frequency wave decreasesmore rapidly in magnitude than a lowfrequency wave.Reason (R): For a given gain, the apertureof a high frequency antenna is smaller thanthat of a low frequency antenna.a. Both A and R are individually true and

R is the correct explanation of Ab. Both A and R are individually true butis not the correct explanation of A

c. A is true but R is falsed.

A is false but R is true91. Assertion (A): The DMA technique is

more efficient than the Interrupt-driventechnique for high volume I/O datatransfer.Reason (R): The DMA technique does notmake use of the Interrupt mechanism.a. Both A and R are individually true and

R is the correct explanation of Ab.


c. A is true but R is falsed.

A is false but R is true92. Consider the following circuit

What is the circuit shown above?a. Miller sweep

b. Bootstrap sweepc. Schmitt triggerd.

Triangular wave generator93. Match List I with List II and select the

correctList I (Application of the Circuit)

A.

DividerB.

Clips input voltage at twopredetermined levels

C. Square wave generatorD.Narrow current pulse generatorList II (Circuit Name)1.

Astable multivibrator2. Schmitt trigger3. Bistable multivibrator.4.

Blocking oscillatorCodes;

A B C Da.

4 2 1 3b. 3 2 1 4c.

4 1 2 3d. 3 1 2 4


How does the above circuit work?a.

As a logarithmic amplitierb. As a negative clipperc. As a positive clipperd. As a half-wave rectifier

95.

Consider the following circuit:

What is the type circuit of given above?a. Monostableb.

Ramp generatorc.

VCOd. Bistable multivibrator


What is voltage difference betweencollector and emitter (VCE) in the abovecircuit?a.

10/3 Vb. 0 Vc.

5 Vd.

3 V

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13/15

13 of 1597.

Consider the NPN transistor circuit shownbelow:

What if the output voltage V0in the abovecircuit?a. 0 V

b. 12 Vc. 9 Vd.

5 V98. Assume that only x and y logic inputs are

available, and their complements x and y

are not available. What is the minimumnumber of 2-point NAND gates requiredto implement xa. 2

b. 3

c. 4d. 5

99.

A, B and C are three Boolean variables.Which one of the following Booleanexpressions cannot be minimized anyfurther?

a. . . . . . . . .Z A B C A B C A B C A B C

b. . . . . . . . .Z A B C A B C A B C A B C

c. . . . . . . . .Z A B C A B C A B C A B C

d. . . . . . . . .Z A B C A B C A B C A B C

100. What is the minimum number of NANDgates required to implement

A AB ABC ?a. 0

b.

1c. 4d. 7

101. Match List I (Logic Gates) with List II

(Characteristics) and select the correctanswer using the codesList IA. HTLB. CMOSC. I2LD.

ECLList II1. High fan-out2. Highest speed of operation

3.

High noise immunity Lowest productof power and delay

Codes;A B C D

a. 3 2 4 1b.

4 2 3 1c. 3 1 4 2

d.

4 1 3 2102. Consider the following logic circuit

What is the required input condition (A,B, C) to make the output X = 1, for theabove logic circuit?

a.

(1, 0, 1)b.

(0, 0, 1)c. (1, 1, 1)d. (0, 1, 1)

103. The output of a two level AND-OR gatenetwork is F What is the output when allthe gates are replaced by NOR gates?(where FDis the dual function of F)a. F

b. F

c. DF

d.

DF 104.

Which one of the following statements iscorrect?a. PROM contains a programmable

AND array and a fixed OR arrayb. PLA contains a fixed AND array and

a programmable OR arrayc. PROM contains a fixed AND array

and a programmable OR arrayd. PLA contains a. programmable AND

array and a programmable NOR.

array105. Which one of the following statementsdescribes the operation of a multiplexer?a. A logic circuit used to generate coded

outputb. A logic circuit used to generate Fs

complementc.

A logic circuit accepts two or moreinputs and allows one of them at a timeto get through the output

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14/15

14 of 15d.

A logic circuit that transmits one inputto several output lines

106. A ROM is to be used to implement asquarer, which outputs the square of a 4-

bit number. What must be the size of theROM?a. 16 address lines and 16 data. lines

b.

4 address lines and 8 data linesc. 8 address lines and 8 data linesd. 4 address lines and 16 data lines

107. Consider the following circuit.

In the above TTL circuit, S2 to S0 areselect lines and X7to X0are input lines. S0

and X0are LSBs. What is the output Y?a. Indeterminable

b. A B

c. A B

d.

C B A 108. Which one of the following statements is

not correct?a.

An 8 input MUX can be used toimplement any 4 variable function

b. A 3 line to 8 line DEMUX can be usedto implement any 4 variable function

c.

A 64 input MUX can be built usingnine 8 input MUXs

d. A 6 line to 64 line DEMUX can be bultusing nine 3 line to 8 line DEMUXs

109. Consider the following statements:For a master-slave J-K flip-flop,1. the toggle frequency is the maximum

clock frequency at which the flip-flopwill toggle reliably

2. the data input must precede the clocktriggering edge transition time by some

minimum time3.

the data input must remain fixed for agiven time after the clock triggeringedge transition time for reliableoperation

4.

propagation delay time is equal to therise time and fall time of the data


1, 2 and 3b. 1, 2 and 4

c.

1, 3 and 4d.

2 3 and 4110. The total number of 1s in a 15-bit shift

register is to be counted by clocking into acounter which is preset to 0. The countermust have which one of the following?a. 4bits

b.

S-bitsc. 16-bitsd. 6-bits

111. Consider the following J-K flip-flop:

In the above J-K flip-flop, J = Q and K=1.

Assume that the flip-flop was initiallycleared and then clocked for 6 pulses.What is the sequence at the Q output?a.

010000b.

011001c.

010010d. 010101

112. Consider, the following statementsregarding registers and latches1. Registers are made .of edge-triggered

FFS, whereas latches are made fromlevel-triggered FFS

2. Registers are temporary storagedevices whereas latches are not

3.

A latch employs cross-coupledfeedback connections

4.

A register stores a binary wordwhereas a latch does not

Which of the statements given above arecorrect?a. 1 and 2b.

1 and 3

c.

2 and 3d. 3 and 4

113. Consider the following shift rights register

The initial contents of the 4-bit serial-inparallel-out, shift right register shownabove are 0110. What will be the contents

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15/15

15 of 15of the register after 3 clock pulses arerequired?a. 0000

b. 0101c. 1010d.

1111114. Match list I (type of N-bit ADC) with List

II (Characteristics) and select the correctanswer:List IA. Flash converterB.

Successive approximationC. Counter rampD. Dual slopeList II1. Integrating type2. Fastest converter3. Maximum conversion time = N bits

4.

Uses a DAC in its feedback pathCodes;A B C D

a. 1 4 3 2b. 1 3 4 2c. 2 4 3 1d.

2 3 4 1115. What is the unit step response of unity

feedback control system having forwardpath transfer function

80

18

G s

s s

?

a. Over dampedb. Critically dampedc. Under dampedd.

Undamped oscillatory116.

Consider the following statements for a.c.series motors:1. The rotor is designed so that its RIX

ratio is small

2. dT/d < 0 where T and are torqueand speed respectively

3.

The reference and control voltagesshould be in phase quadrature, but theirmagnitudes need not be equal


1, 2 and 3b.

1 and 2c. 2 and 3d. 1 and, 3

117. An open loop system has a transferfunction

3 2

1

1.5 1s s s . It is converted into a

closed loop system by providing anegative feedback having transfer function20 (s + 1). Which one of the following iscorrect?The open loop and closed loop systems

are, respectivelya. stable and stableb.

stable and unstablec. unstable and stabled. unstable and unstable

118. A tachometer feedback is used as an innerloop in a position control servo-system.What is the effect of feedback on the gainof the sub-loop incorporating tachometerand on the effective time constant of thesystem?a. Both are reducedb.

Gain is reduced but the time constant isincreased

c. Gain is increased but the time constantis reduced

d. Both are increased119. Consider the following statements

Feedback in control system can be used1. to reduce the sensitivity of the system

to parameter variations anddisturbances

2. to change time constant of the system

3.

to increase loop gain of the systemWhich of the statements given above arecorrect?a. 1, 2 and 3b. 1 and 2c.

2 and 3d. 1 and 3

120. Which one of the following statements iscorrect in respect of the theory of stability?a. Phase margin is the phase angle

lagging, in short of 1800, at the

frequency corresponding to a gain of10

b. Gain margin is the value by which thegain falls short of unity, at a frequencycorresponding to 90 phase lag

c. Routh-Hurwitz criterion can determinethe degree of stability

d. Gain margin and phase margin are themeasure of the degree of stability

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