1. In an amplitude modulated system if the total power is 600W and the power in the carrier is 400W, the modulation index is
a.
-0.5

b.
0.75

c.
0.9

d.
1


2. The channel capacity under the Gaussian noise environment for a discrete memoryless channel with a bandwidth of 4MHz and SNR of 31 is.
a.
20 Mbps

b.
4 Mbps

c.
8 kbps

d.
4 kbps


3. In satellite communication, frequency modulation is used because satellite channel has
a.
High modulation index

b.
Small bandwidth and negligible noise

c.
Large bandwidth and severe noise

d.
Maximum bandwidth and minimum noise


4. For a 3-um-diameter optical fiber with core and cladding indexes of refraction of
1.545 and 1.510, respectively. The cut off wavelength is.
a.
2.3um

b.
I.29um

c.
I.5um
d.3.24um



5. A 12-bit ADC is operating with a Ius clock period and total conversion time is seen to be l4us always. The ADC must be of the type
a.
Flash type

b.
Counting type

c.
Integrating type

d.
Successive approximation type


INDIAN SPACE REASERCH ORGANISATION Page 2 of17



6. Consider the analog signal 3coslOOnt. Ifthe signal is sampled at 200Hz, the discrete time signal obtained will be
a.
3cos(nn/4)

b.
3cos(nn/2)


c.
3cos(nn)

d.
3cos(nn/3)


7. In VHDL all the statements written inside a process statement are
a.
Concurrent

b.
Sequential

c.
Both and

d.
None ofthe above


8. A microprocessor with 12-bit address bus will be able to access kilobytes of memory
a.
0.4

b.
2

c.
10


d. 4
9. A practical current source is usually represented by
a.
A resistance in series with an ideal current source.

b.
A resistance in parallel with an ideal current source.

c.
A resi'stance in parallel with an ideal voltage source.

d.
None of the above.


10. The dominant mode in a rectangular wave guide is TEo, because this mode has
a.
No attenuation

b.
No cut off

c.
No magnetic field component

d.
The highest cut-off wavelength


11. A PN junction in series with a 100 ohm resistor is forward biased so that a current of 100 rnA flows. If voltage across the combination is instantaneously reversed to 10V at time t the reverse current that flows through the junction at t 0 is approximately given by.
a.
OmA

b.
200mA

c.
50 rnA

d.
100 rnA


..... INDIAN SPACE REASERCH ORGANISATION Page 3 of17


I ELECTRONICS -2011 SET-A I
12. Ripple factor for a halfwave rectifier is
a.
1.65

b.
1.45

c.
1

d.
1.21


13. is a primitive that can execute code. It contains an instruction pointer (=program counter) and sometimes has its own stack
a.
Process

b.
Task

c.
Kernel

d.
Thread


2
14. Ifa andparethe roots oftheequationx thenIa2is
a. p2+
b. 2q
c.
p2-2q

d.
p-2q


15. A signal mt is band limited to 3.6 kHz and the three other signals and are band limited to 1.2 kHz each, and these signals are transmitted by means of TDM. Then, what will be the transmission bandwidth of the channel.
a.
7.2 KHz

b.
14.4 KHz

c.
3.6 KHz

d.
2.4 KHz


16. For a 10 bit PCM system the signal to quantization noise ratio is 62dB. If the number of bits is increased by then the signal to quantization noise ratio will
a.
Increase by 6 dB

b.
Increase by 12 dB

c.
Decrease by 6 dB

d.
Decrease by 12 dB


17. The modulation normally used with the digital data is­
a.
FM

b.
AM

c.
SSB


d. QPSK
INDIAN SPACE REASERCH ORGANISATION Page 4 of 17


I ELECTRoNICS -2011 SET-A I
18. The critical angle 8c in an optical fiber is given by . Where nl is refractive index of medium 1 and n2 is the refractive index of medium 2.
a.
Sin-I nl)

b.
Sin-I n2)

c.
Sin-l nl)

d.
Sin-l n2


19. In a JK flip flop we have J and K 1. Assuming that the flip flop was initially cleared and clocked for 6 pulses, the sequence at the Q output will be
a.
010000

b.
011001

c.
010010

d.
010101


C J Q
1 K
ciack

20. Which of the following system is linear
a. yen)
b.
yen) B

c.
yen)

d.
yen)


21. Which of the following operator cannot be synthesized by VHDL synthesis tools
a.
b.
c.
d.

22. Which of the following statements with reference to a generic microprocessor is correct?
a.
Instruction cycle time period is exactly equal to machine cycle time period

b.
Instruction cycle time period is shorter than machine cycle time period

c.
Machine cycle time period is shorter than instruction cycle time period

d.
Instruction cycle time period is exactly half of machine cycle time period


23. An electric iron designed for 110V AC supply was rated at SOOW. It was put across a 220V supply. Assuming that at 110V it supplied SOOW output (i.e no losses) at the new voltage it will supply
a.
2500W

b.
250W

c.
500W

d.
2000W


24. A very iossy, A/4 long, 50 ohm transmission lineis open circuited at the load end. The input impedance measured at the other end of the line is approximately.
a.
0

b.
OC!

c.
50 ohm

d.
none of the above


25. For the 2N338 transistor, the manufacturer specifies P max =100mW at 25° C free air temperature and the maximum junction temperature, Tj max 125°. Its thermal resistance is
a.
10° C/W

b.
100° C/W

c.
1000° C/W

d.
10,000° C/W


26. In a Class AB amplifier, the current flows through the active device for
a.
Less than half ofthe duration of input cycle

b.
Half duration ofinput cycle

c.
More than half but less than full cycle duration

d.
Full duration of input cycle


27. Which of the following is not true regarding a preemptive kernel
a.
If a high priority thread becomes ready to run, low priority thread is preempted

b.
The kernel checks highprinrity-ready to when evc:rcalted---.

c.
The executing thread is never interrupted

d.
There are special demands on communication between threads and handling common resources


.... INDIAN SPACE REASERCH ORGANISATION Page 6 ofl7


X x2
28. The solution of differential equation dy/dx is
X
a. eY e
b. eY- eX= c
c.
x-eY

d.



29. The intermediate frequency of a super-heterodyne receiver is 450 KHz. Ifit is tuned to 1200 KHz, the image frequency will be
a.
750 KHz

b.
900 KHz

c.
1600 KHz

d.
2100 KHz


30. The bandwidth of a bit binary coded PCM signal for modulating a signal having bandwidth of Hz is
a. fIN Hz;
b. f
c.
Nf

d.
N


31. Go-stationary satellites are placed in equatorial orbits at the height approximately
a.
1000 km

b.
15000 km

c.
25000 km

d.
36000 km


32. For a single mode optical cable with 0.25dB/km loss, the optical power 100km from a O.lmW source will be
a.
-30dBm

b.
-35dBm

c.
-40dBm

d.
-45dBm


33. The function of a strobe function in digital system is
a.
To reset memory register.

b.
To check the functioning ofa logic gate

c.
To avoid race problem .

d.
To tri-state the output ofthe register


.... INDIAN SPACE REASERCH ORGANISATION Page 7 of17


I ELECTRONICS -2011 SET·A

40. For a class B amplifier providing a 20V peak signal to 16 ohm load and a power supply ofVcc 30V, the efficiency will be.
a.
52.3%

b.
25.65%

c.
75%

d.
78.6%


41. When a microprocessor interfaces with a peripheral or memory device, the normal timing of the microprocessor may need to be altered by introducing
a.
Latching

b.
Wait states

c.
Tristate logics

d.
None of the above


42. tr/2f(Cos 3X dx
o
a.
3/2

b.
2/3

c.
8/9

d.
8/13


43. In phase modulated signal, the frequency deviation is proportional to
a.
Frequency only

b.
Amplitude only

c.
Both and

d.
none of the above


44. For a fast communication which of the following requirements have to be met
a.
Large bandwidth

b.
High SIN ratio

c.
High channel capacity

d.
None ofthe above


..", INDIAN SPACE REASERCH ORGANISATION Page 9 of17
,£5ro



I ELECTRONICS -2011

34. The impulse response of a linear time invariant system is h The response for the input signal is
a.


b.


c.


d.



35. Which of the following statement regarding a constant is not true
a.
Constant defined in a package can be referenced by any entity or architecture for which package is used.

b.
The value of constant can be changed with in the design description

c.
Constant defined in an architecture is visible only to that architecture

d.
Constant defined in a process declarative region is not visible outside that process


36. In a 8085 microprocessor system with memory mapped I/O
a.
1/0 devices have 8 bit address

b.
1/0 devices are accessed using IN and OUT instructions.

c.
There can be maximum 256 input and 256 output devices

d.
Arithmetic and logic operations can be directly performed with 1/0 data


37. The Thevenin and Norton circuits are
a.
Single frequency equivalent circuits

b.
Multi frequency equivalent circuits

c.
Equivalent independent of frequency

d.
Band frequency equivalent circuits


38. A broadside array operating at 100 cm wavelength consist of 4 halfwave dipoles spaced 50 cm apart. Each element carries radio frequency current in the same phase and of magnitude 0.5A. The radiated power will be if the radiation resistance is 146 ohm.
a.
146W

b.
73W

c.
36.5 W

d.
18.25 W


39. An NPN transistor has a beta cut off frequency of 1MHz, and a common emitter short circuit low frequency current gain Po of 200. its unity gain frequency fT and the alpha cut-off frequency fa respectively are
.­
a.
200 MHz, 201 MHz

b.
200 MHz, 199 MHz

c.
199 MHz, 200 MHz

d.
201 MHz, 200 MHz


t ,..... INDIAN SPACE REASERCH ORGANISATION Page 8 of 17
.151"'0


I ELECTRONICS -2011 SET-A I

45. For an earth station transmitter input power of 40dBW with a back off loss of 3dB, a total branching and feeder loss of 3dB, and a transmit antenna gain of 40 dB, determine the EIRP.
a.
40dBW

b.
74dBW

c.
34dBW

d.
80dBW


46. is used to describe the light gathering or light collecting ability of an optical fiber
a.
Critical angle

b.
Cut-offwavelength

c.
Numerical Aperture

d.
Acceptance angle


47. has the maximum fan out capacity
a.
MOS

b.
CMOS

c.
ECL

d.
RTL


48. IfZ transform ofx(n) is thentheZ transform ofx(n-k)is
a.
X(Z·k

b.
X(Zk

c.
Z·kX(z)

d.
ZkX(Z)


49. The following code will implement a
process begin
if (elk then


end if;
end process

a.
Positive edge triggered D flip flop

b.
Negative edge triggered D flip flop

c.
A latch

d.
None ofthe above.


:...... INDIAN SPACE REASERCH ORGANISATION Page 10 of 17
15t'0

SET·A I


50. The greatest negative number which can be stored in a 8-bit register using complement arithmetic is
a.
-256

b.
-255

c.
-127

d.
-128


51. Two coupled coils have self inductances L1 10mH and L2 20mH. The co­efficient of coupling being 0.75 in the air. Voltage in the second coil when the current in circuit is given by I 2 sin (314t) A is .
a.
3.14 cos (314t) V .

b.
3.33 sin (314t) V

c.
6.66 cos (314t) V

d.
6.28 cos (314t) V


52. In a radar system, ifthe peak transmitted power is increased by a factor of 16 and the antenna diameter is increased by a factor of2, then the maximum range will increase by a factor of
a.
16

b.
8

c.
4


d.
53. The transconductance gm of an FET in the saturation region equals

b. -21oss_ri -VGsJ 2 VpL Vp

d.

INDIAN SPACE REASERCH ORGANISATION
Page 11 of 17
IELECTRONICS -2011 -SET-A I

54. The transistor amplifier with 85% of efficiency is likely to be
a.
Class A

b.
Class B

c.
Class AB

d.
Class C


55. A run-time stack cannot be used in a round-robin scheduling system because of the nature of scheduling.
a.
LIFO (Last in First out)

b.
FIFO First in First out)

c.
FILO (First in Last out)

d.
None ofthe above


56. 51) is same as
a.
b.
3- i

c.
5- 5i


d.
57. The modulation index of an amplitude modulated wave is changed from 0 to 1. the transmitted power is
a.
Doubled

b.
Halved

c.
Increased by 50 percent.

d.
Unchanged.


58. In a communication system, each message or is transmitted three times in order to reduce the probability of error. The detection is based on the majority rule at the receiver. IfPc is the probability of bit error, the probability of error for this communication channel will be
a.
3Pc2 -2Pc3

b.
1- Pc2_Pc3

c.
Pc3

d.
Pc2(1


59. For a satellite transponder with a receiver antenna gain of 12 dB an LNA gain of 10 dB, and equivalent noise temperature of26 dBK- the G/Te is
a. 4 dBK-1
b. dBK-L
c.
26 dBK-1

d.
-26 dBK-1


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60.
61.

62.

63.

64.


I
current is the leakage current that flows through a photo diode with no
input used in as light detectors.
a. Leakage
b. Dark
c. saturation current
d. Detection

The figure of merit of a logic family is given by
a.
Gain bandwidth product

b.
(propagation delay time) (power dissipation)

c.
fanout propagation delay time)

d.
(noise margin) (power dissipation)


is defined as the time delay that a signal component of frequency ro undergoes as it passes from the input to output of the system.
a.
Phase delay

b.
Group delay

c.
Frequency deviation

d.
Latency


Which statement is true regarding a behavior modeling in VHDL
a.
There can be more than one process statement in an architecture which will interact concurrently

b.
Behavioral style of architecture can have only concurrent assignment statements

c.
Process is not a single concurrent statement

d.
A process need not have sensitivity list for proper implementation


The process of imitating one system with another so that the imitating systems accepts the same data, executes same programs and achieves same results as the imitated systems is known as
a.
Simulation

b.
Modification

c.
Translation

d.
Emulation


:..... INDIAN SPACE REASERCH ORGANISATION Page 13 of 17


I ELECTRONICS -2011 SET-A
65. The values of Land C in series RLC circuit that resonates at 1.5 KHz and consumes SOW from a SOV ac source operating at the resonant frequency. The bandwidth is 0.75 KHz.
a.
R=50ohm,L= 1-0.6mH,C= 1.06uF.

b.
R=500ohm,L= 10.6mH,C= 10.6uF.

c.
R=50ohm,L=1.06mH,C=10.6uF.

d.
R=500ohm,L= 1.06mH,C= 1.06uF.


66.
When VSWR is the magnitude of the reflection co-efficient will be

67.
The conductivity of the intrinsic germanium at 3000K is . When, nj at 300oK"'; 2.5 X 10l3/cm and""n and,..,p in germanium are 3800 and 1800 cm2Ns respectively.

a.
0.224 S/cm

b.
0.0224 S/cm

c.
2.24S/cm

d.
0.00224 S/cm



68.
As compared to a full wave rectifier using 2 diodes, the four diode bridge rectifier has the dominant advantage of

a.
Higher current carrying

b.
Lower peak inverse requirement

c.
Lower ripple factor.

d.
Higher efficiency.



69.
In a real time system, the simplest scheme that allows the operating system to allocate memory to two processes simultaneously is

a.
Over lays

b.
Pipeline

c.
Swapping

d.
None ofthe above



70.
(cos 58 sin 58)2 is same as

a. cos 100 i sin 100

cos 25e-=TsiJi 258

c.
(cos0 +isin OylO

d.
(cos0-isin OrlO



71.
In case of which of the following, an increase on the modulation index leads to increase in bandwidth

a.
PM

b.
FM

c.
AM

d.
Both and



72.
Four voice signals, each limited to 4 kHz and sampled at Nyquist rate, are converted into binary PCM signal using 256 quantisation levels. The bit transmission rate for the time division multiplexing signal will be

a.
8 kbps

b.
64 kbps

c.
256 kbps.

d.
5126 kbps



73.
Ifa counter having 10 FFs is initially at what count will it hold after 2060 pulses?

a.
000000 1100

b.
000001 1100

c.
000001 1000

d.
000000 1110



74.
The output of a circular convolution performed on two signals and is


a.
b. 13
c. Yz.
d. 1.

INDIAN SPACE REASERCH ORGANISATION . Page 14 of17


C
a.
14, 16, 14}

b.
16, 14, 16}

c.
14, 12, 14}

d.
12, 14, 12}


75. When using a sequential code to design a combinational logic in VHDL, if complete truth table is not defined, the synthesis tool will implement a which is not required.
a.
Clock buffer

b.
Buffer

c.
Flip Flop

d.
Latch


76. In what order the elements of a pushdown stack are accessed?
-a. First In-First Out (FIFO)
b.
Last In Last Out (LILO)

c.
Last In First Out (LIFO)

d.
None ofthe above


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77. What is the value of C such that equivalent capacitance across x-y is SF
x I
=k1F I 3F 1


I 3F
2F
4F
1F

2F C
F

a.
20F

b.
23F

c.
22F

d.
21F


78. A wave guide section in a microwave circuit will act as a
a.
Low pass filter

b.
Band pass filter

c.
High pass filter

d.
Band stop filter


.""" INDIAN SPACE REASERCH ORGANISATION Page 16 of11


79. A 24V, 600mW Zener is to be used for providing a 24V stabilized supply to a variable load. Assume that for proper Zener action, a minimum of 10 mA must flow through the Zener. Ifthe input voltage is 32V, what would be the value of R and the maximum load current?
R



a.
320 ohm, lOrnA

b.
400 ohm, l5mA

c.
400 ohm, lOrnA

d.
320 ohm, l5mA


80. The value of x at which y has a minimum for y =x2 -3x 1 is
a.
b.
3/2

c.
0

d.
None ofthese


.."" INDIAN SPACE REASERCH ORGANISATION Page 17 of17
tl

79. A 24V, 600mW Zener is to be used for providing a 24V stabilized supply to a variable load. Assume that for proper Zener action, a minimum of 10 mA must flow through the Zener. Ifthe input voltage is 32V, what would be the value ofR and the maximum load current?




a.
320 ohm, lOrnA

b.
400 ohm, l5mA

c.
400 ohm, lOrnA

d.
320 ohm, l5mA


80. The value of x at which y has a minimum for y =x2 -3x 1 is
a.
b.
3/2

c.
0

d.
None ofthese


INDIAN SPACE REASERCH ORGANISATION Page 17 of17