This preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: INDIAN SPACE RESEARCH ORGANISATION ' """"""
,, . ,, r ,, LVViALOFV 18 ELECTRONICS AND COMMUNICATION ENGINEERING An LTI system has the input signal x(n). Which of the following sequence of
operations is most appropriate to get output y(n) = x(n  M/L). a) Interpolation by L, Delay by M, Decimation by L b) Delay by M, Interpolation by L, Decimation by M c) Decimation by L, Delay by M, Interpolation by L d) Interpolation by L, Decimation by L, delay by M Consider a low pass random process with a white noise power spectral density
Sx(oo) = N/2 where ZnB 5 to _<_ ZnB
0 elsewhere
The Autocorrelation function Rx(1:) is
a) 2NBsinc(2nBr)
b) nNBsinc(27rBr)
c) NBsinc(27tB1,)
(1) none of the above Polezero plot of a digital ﬁlter is shown below, what is the type of ﬁlter? a)Low Pass b) High Pass c) Band Stop (1) All Pass Determine the DTFT of the sequence y[n] = (n+1)ozn u[n],‘ [al < 1 . u[n] is unit step
sequence. .
a) Y(e’°’) = 1 / (1  a e"‘°)2 b) Y(e1'_°’) = 1 / (1 + (1 cf”?
c) Y(e"”) =a / (1  a e"‘°)2
d) none of the above The function f(t) has the Fourier transform g(oo). The Fourier transform of g(t) is
a) f(oa) / 2n b) f(—co) / 27:
c) 21: f(03) d) none of the above Electronics and Communication Engineering I. SET—A INDIAN SPACE RESEARCH ORGANISATION ...... ' ...........
’ ' ‘ . " """“""~*“2”bF 18 ELECTRONICS AND COMMUNICATION ENGINEERING 6 The purpose of Design for Test (DFT) process in ASIC design ﬂow is
a) To capture functional errors
b) To capture manufacturing defects
c) To capture timing violations
(1) For radiation mitigation 7 The coupling between the two inductors is increased from zero in the circuit shown.
' Which of the following statements is true?., " a) The resonant frequency will increase and the Q will decrease
b) The resonant frequency and Q will both increase.
c) The resonant frequency and Q will both decrease
d) The resonant frequency will decrease and the Q will increase Electronics and Communication Engineering B ‘ SET—A 8 10 INDIAN SPACE RESEARCH ORGANISATION  ' ...........
  — r ~~A~V#3_OF 18 ELECTRONICS AND COMMUNICATION ENGINEERING Write a Boolean expression for Z in terms of A, B, C, D and E. You need not simplify
the expression. Vs a) [{(A+B)  (D'E)}+ C]
b) [{(A  B) + (D + 13)}  C]
c) [{(A ~ B) + (D + EBE]
(1) False A parallel plate capacitor of 100 pf having an air dielectric is charged to 10 kilovolts.
It is then electrically isolated. The plates are pulled away from each other until the
distance is ten times more than before. Estimate the energy needed to pull the plates. 
a) 0.05 Joules b) 50 Joules c) 500 Joules " d) 50 Joules How could Schroedinger’s equation be relevant in the practical design of a Cathode—
Ray Tube? a) To optimize the colour quality b) To optimize the picture sharpness c) It is not relevant, because the CRT contains no crystalline lattice structure d) Its effects are negligible, as the electron wavelength is very small compared to the
spot size Eectronics and Communication Engineering E. SETA Page: INDIANWSPACE RESEARCH ORGANISATION a. M._ M, 777 :A:OWI; ié—u. 11 When compared with stripline, the major disadvantage of microstrip line is a) Not amenable for printed circuit technique.
b) More expensive and complex to manufacture.
c) Bulkier and voluminous. ‘ (1) More likely to radiate. 12 The disadvantage of single—stub matching as compared to doublestub matching, is
that a) The stub position has to be adjustable b) Only shunt stub can be used c) Only resistive load can be matched (1) Useful only in two Wire transmission line 13 A charge Q2 =8.854 ><10'9 C is located in a vacuum at P2 (2,3,1). The force on Q2 due to
a charge Q1=4n ><10'3 C at 191 (2,2,1) is .
a) ay N b) 5.4a,(+6Bay5.4aZ N c) 5.4ax6.3ay—5.4az N d) None 14 If a material contains 1020 molecules/m3, each molecule having a moment of 8.854 XIO'27 C—m parallel to an electric ﬁeld of 105 V/m, then its dielectric constant is
a) 2.2 b) 2 c) 4 d) 12 15 If every minor of order ‘r’ of a matrix ‘A’ is zero, then rank of ‘A’ is
a) greater than ‘r’ b) equal to ‘r’
c) less than or equal to ‘r’ d) less than ‘r’ 16 Which of the following is true
‘ a) The product of the eigenvalues of a matrix is equal to the trace of the matrix
b) The eigenvalues of a skewsymmetric matrix are real
c) A is a nonzero column matrix and B is a nonzero row matrix, then rank of AB is
one
d) A system of linear non—homogeneous equations is consistent'if and only if the rank
of the coefﬁcient matrix is less than or equal to the rank of the augmented matrix Electronics and Communication Engineering I SETA Page: Ag 1:;0; {8— INDIAN SPACE RESEARCH ORGANISATION 17 What is the maximum clock frequency at which following circuit can be operated . without timing violations? Assume that the Combinational logic delay is 10 ns and
the clock duty cycle varies from 40% to 60 °/o. Combinational
Logic Clock a) 100 MHz b) 50 MHz c) 40 MHZ d) 25 MHz 18 Following shift register is initially loaded with the bit pattern “1010”. After how
many clock cycles will the content of shift register be “1010” again? clock
Serial
input
a) 5 b) 9 c) 7 d) 15
19 Which one of the following is the lowest level of abstraction for representation of a
digital system? ‘
a) VHDL/Verilog
b) GDSII
c) Gate level netlist
d) SystemC 20 The content of the accumulator of 8085 microprocessor after execution of the
following instructions will be MVI A, A7h
ORA A
RLC a) FFh ' b) 4Fh ' c)3Fh d) CEh Electronics and Communication Engineering B SETA Page:
' “VT ’Tﬁmdf’f '1 8 INDIAN SPACE RESEARCH ORGANISATION”. 21 For CMOS implementation of 2 input XOR logic gate, how many nMOS and pMOS transistors are required?
a) 2 nMOS and 2 pMOS ' b) 3 nMOS and 3 pMOS c) 6 nMOS and 6 pMOS d) 8 nMOS and 8 pMOS 22 Which of the following principles is applied while designing the output matching
network for a high power Class—C ampliﬁer?
a) Maximum Power Transfer Theorem b) Norton’s Theorem
c) Thevenin’s Theorem d) Power = (voltage)2 / RL 23 Find the approximate output impedance of the VCCS (voltagecontrolled current ‘
source) based circuit at port V0. Vin 4. Vco a) 0.01 (1 b) 100 (2 c) 100 kg d) 10 M9 24 Which of the following parameters of a Silicon Schottky Diode is higher than
that of a corresponding PN junction diode? .
a) Forward voltage drop b) Reverse recovery current c) Reverse recovery time d) Reverse leakage current Electronics and Communication Engineering I: SETA Page: INDIAN SPACE RESEARCH ORGANISATlON ——
7 ' "“ "mAr‘rrrerri*7—~.OFV 18 ELECTRONICS AND COMMUNICATION ENGINEERING 25 Assume the intrinsic standoff ratio for the UJT is 0.8 for the relaxation oscillator
circuit given below. The frequency of oscillation of this circuit is approximately equal to 12Vdc
a) 1.43 kHz b) 620 Hz c) 7kHz d) 1.6kHz
26 The approximate frequency of oscillation of the circuit shown below is
015V
a) 8.3kHz b) 16.6kHz , c) 7.2kHz d) 3.6kHz Electronics and Communication Engineering B SETA 28 29 30 31 32 33 INQIAN WSEACE RESEARCH ORGANISATIQNW "7 r7 ““8 ’OF 1 8 ELECTRONICS AND COMMUNICATION ENGINEERING A unit step voltage travels from left to right along an inﬁnite transmission line. It hits
an inductive discontinuity at t=0. What will be the waveform immediately to the left of
the discontinuity? a) Positive spike on a unit step , b) Unit step with reduced rise time c) Attenuated unit step d) Magniﬁed unit step A lossy open stub having a length of 1/32 wavelength, is approximately equivalent to
a) A small capacitor in shunt with a small resistor b) A small capacitor in shunt with a large resistor
c) A small inductor in shunt with a small resistor
d) A large inductor in shunt with a large resistor Ampere's law relates a) Electric ﬁeld and Charge b) Electric ﬁeld and Current
c) Magnetic ﬁeld and Current d) Magnetic ﬁeld and Charge Across which type of boundary does the electric ﬁeld have a continuous tangential
component? a) Charge free boundary \ b) Current free boundary
c) Any boundary d) Charged boundary Laplace Transform of ea t"
a) n/(sa)" 1 b) n!/(s+a)"+1
c) n!/(sa)"+1 d) 1/(s—a)“+1 For oo < x < oo 2&— 1' < y < 1, the partial differential equation
x2 L21; 2 __=
(4131):2 0 1s
a) parabolic b) Hyperbolic
c) Elliptic d) Nature connote be predicted A CMOS digital circuit consumes P watts of dynamic power while operating at 20 MHz clock frequency and 5V supply. What will be its dynamic power consumption
if the clock frequency is increased to 40 MHz and supply voltage is decreased to 2.5V?
a) PM , b) P/2 c) P d) 2P Electronics and Communication Engineering II: SETA 34 35 36 37 38 39 Electronics and Communication Engineering INDIAN SPACE RESEARCH ORGANISATION ELECTRONICS AND COMMUNICATION ENGINEERING A communication channel with Additive White Gaussian Noise, has a bandwidth of 4
kHz and SNR of 31dB. Its channel capacity is a) 1.6 kbps b)20 kbps c) 32 kbps d) 256 kbps If the total power of an amplitude modulated signal is 600W and the carrier power is
400W, the modulation index is ' a) 0.75 b) 0.5 c) 0.25 d) 1 What is the advantage of Offset QPSK (OQPSK) compared to conventional QPSK?
a) Constant envelope b) Bandwidth efﬁciency c) Simple demodulator _ d) All of above An angle modulated signal with carrier frequency coc = 271 X 105 is described by the
equation s(t) = 10 cos (coct + 5 sin(30007ct) + 10 sin(2000nt) ). What is the frequency
deviation Af ? a) 12387.32 Hz b) 17500 Hz 0) 20000 Hz d) 15000 Hz The Fourier transform of a signal x(t) = e'4ltl is
a) 8 /(16 + of) b) 8 /(16 — 032)
c) 4 /(16 + (02) d) —4 /(16 + col) What is the output waveform V0 for a sinusoidal input of peakpeak amplitude of 4V.
Assume that Z1 and Z2 are two identical Zener diodes of 4.7V, and R1=10kohm and
R2=20kohm. 1 a) Same as input b) Sinusoidal waveform with 5.4V peak c) Sinusoidal waveform clamped to +/ 4.7V
d) Sinusoidal waveform clamped to +/— 5.4V E I SET—A 41 42 For a particular toroidal inductor core, the inductance value obtained for 50 Turns is
ZOOuH. If two such inductors are wired in parallel, the resulting inductance is a) ZOOuH b) 50uH ' c) 400uH d) IOOuH
The magnetic equivalent of Ohm’s Law is a) Lenz’s Law b) Faraday’s Law c) Rowland’s Law d) Maxwell’s Law It is required to design a class B output stage (as shown below) to deliver an average
output power of 12.5W to a load of 4!). The power supply is selected so that Vcc is 5V greater than the peak output voltage. Determine the power conversion efﬁciency, of
the circuit. +Vcc V a) 48% . b) 50% c) 52% d) 54% Electronics and Communication Engineering I l : I SETA Page:
”hummu— OF 18 INDIAN SPACE RESEARCH ORGANISATION (a) A resistance, capacitor and inductor in series (b) A resistance, capacitor and inductor in parallel
(c) A resistance in shunt with a series combination of an inductor and a capacitor
((1) A resistance in series with a shunt combination of an inductor and a capacitor 44 A coaxial transmission line carrying an RF signal is perfectly matched to the load.
Consider the crosssection of the line, at a plane where the instantaneous voltage is at
its maximum value. How will the curl of the Eﬁeld vary over this crosssection? a) Increases from the center to the outer conductor
b) Decreases from the center to the outer conductor
c) Zero everywhere _ d) Constant value proportional to the RF voltage 45 The continuity of the tangential ﬁeld component at the interface of two media for
normal incidence of a plane wave requires a)T=1r b)T=1+r c)T=r d)'l"¢1" 46 Which mode of a circular waveguide will have the lowest attenuation? a) TE11 Mode b)TM01 M’ode c) TE21 Mode d) TE01 Mode 47 If (p = 2x2y—xz3, then the Laplacian of (p is
a) 4yz—6xz b) 4z6xy c) 4y—6xz d) 2xy6yz Electronics and Communication Engineering I I l SETA 48 What does the following integral evaluate to?
7r/ 2 [sin6 ads 0 a) 5 n/16 b) 5 75/8 c) 0 d) 5 7r/32 49 A signal with two frequency components at 6 kHz and 12 kHz, is sampled at the rate
of 16 kHz and then passed through a Low Pass ﬁlter having a cut—off frequency of 16
kHz. The output signal of the ﬁlter
a) is an undistorted version of the original “signal
b) contains the 6 kHz component and a spurious component of 4 kHz
c) contains only the 6 kHz components d) contains both the components of the original signal and two spurious components
of 4 kHz and 6 kHz 50 What is the greatest allowable PRF for unambiguous reception in a radar having a
maximum range of 120 km? a) 1250 pps b) 2500 pps c) 1200 pps d) 5000 pps 51 A microprocessor has a cache memory with access time of 2 ns and a main memory
‘ with access time of 10 us. If the cache miss ratio is 0.6, what is the average memory
access time? a) 6.8 ns b) 6 ns c) 5.2 ns d) 12 ns 52 Consider the following assembly code for a hypothetical RISC processor with a 4stage pipeline (Instruction Fetch, Decode/Register Read, Execute and Write).
add r1,r2,r3 // r1 = r2+r3
sub r4,r1,r3 // r4 = r1r3
mul r5,r2,r3 // r5 = r2 *r3 Identify the possible pipeline hazard and the affected instruction. a) Read after write hazard during mul b) Read after write hazard during sub c) Read after write hazard during add (1) Write after write hazard during mul 53 A zero memory source emits six messages with probabilities 0.3, 0.25, 0.15, 0.12, 0.1
and 0.08. If binary Huffman coding is used, what will be the average code length?
a) 2.45 bits b) 3.45 bits c) 2.54 bits (1) 3.54 bits Electronics and Communication Engineering '9 SETA 54 55 56 INDIAN SPACE RESEARCH ORGANISATION 1 :iiig:;;——1—.§..__ In the circuit given below, assume that Vcc= 15V; Z1, Z2, Z3 & Z4 are identical zener
diodes with breakdown voltage of 5V; R1: R4 = 5kg, R2=R3=10kﬂ.
Find Vo when Q1 is OFF. a) 7.5 V . b) 5V c) 10V d) 8.33V
Assume that Vi = 2V; R3 = 109; B of Q1 = 50; Vcc = 15V. Find Iout a) 3.92mA b) 4mA c) 6.84mA , d) 2.8mA A sample and hold ampliﬁer is connected to an ADC. The acquisition time of the
sample and hold ampliﬁer is 10 usec and the conversion time of the ADC is 15 usec.
What is the highest possible data rate? a) 100 ksamples b) 400 ksamples c) 40 ksamples d) 66 ksamples Electronics and Communication Engineering I E. V SETA llylPlAN SPACE 3§§EAVRcH ORGANISATIQNW ,, ELECTRONICS AND COMMUNICATION ENGINEERING 57 In an inverting OPAMP, the input bias current is 1uA, and the input and the
feedback resistances are both 1M9. What will be the output voltage for an input voltage of 2.5V?
21) 2.5V b) 3.0V . c) 3.5V d) 4.0V
58 Which of the following devices can be used for generating a PWM signal?
a) Comparator b) 555 timer ’
c) Counter and magnitude comparator d) All the above 59 A microwave receiving antenna on a satellite is pointing towards the earth. The antenna beamwidth is 50 degrees. The earth subtends 5 degrees at the satellite. What
will be the noise temperature of the antenna? a) 30 degrees Kelvin ' b) 5 degrees Kelvin
c) 300 degrees Kelvin = d) 1000 degrees Kelvin  60 Estimate the magnitude and phase of the element S“ of the Smatrix of the circuit
shown below. Assume an operating frequency of 25 MHz. n
a a) 25 A 180° b) 25 4 0° c) 0.334 180° d) 0.33 1 0° 61 The electric ﬁeld measured in the far ﬁeld of an antenna at a distance of 50m is lV/m.
The average power density at a distance of 500m from the antenna is
a) 26.6uW/m2 b) 0.1uW/m2 c) lOuW/mz , d) 13.3uW/m2 62 A quarter wave monopole antenna is situated above a perfectly conducting ground
plane. It is driven by a 50V source at 500MHz through an internal impedance of
63.59. The average power radiated by the antenna is 21) 3937W/m2 b) 456W/m2 c) 68.49W/m2 d) 45.6W/m2 Electronics and Communication Engineering I I I SETA Page: INDIAN SPACE RESEARCH ORGANISATION _______, 1 215 OF 18
ELECTRONICS AND COMMUNICATION ENGINEERING 63 Directional derivative of U=2x3y—3yzz at P(1,2,—1) in a direction towards Q(3,1,5) is
a) 90/7 b) 30/7 c) 90/49 (1) None of the above 64 Consider the equation Re(l/z)=c, where z is a complex number, c is a nonzero constant
and Re() represents the real part. The equation describes a a) Straight line b) Parabola c) Circle (1) None of the above 65 How many adders are required to realize a 256 point radix—2 FFT using
decimationintime?
a) 256 b) 1024 c) 4096 ‘ d) 2048 66 A uniformly distributed random signal x{n] with mean mx=2 and variance 65:3, is passed through a 3—point movingaverage ﬁlter having an impulse response
{h[n]}={1/3, 1691/3}. What will be the mean and variance of output? a) my =2, 0; =1 b), my =2, 0; =3 c) my =1, 0'}, = 01) my =3, 0'}, =3 67 A sine wave is applied to a balanced modulator. The peak output envelope power is 1000 times the minimum output envelope power. Estimate the carrier suppression in
dBc. a) 24 dBc b) 30 dBc c) 36 dBc d) 40 dBc 68 Consider a single error correcting (7, 4) cyclic code with generator matrix
g(x) = x3 +x2+1. What will be the transmitted data if received vector r is 1101101? a) 1100 b) 1010 c) 0001 d) 1110 69 Consider a Golay’s (23,12) code with t bits of error correction capability. For what '
value of t will the code exactly satisfy the Hamming bound ? a) 2 b) 3 c) 4 d)5 70 The maximum range of a monostatic Radar is R. If a target having a Radar cross—
section of 10m2 exists at R/2, what should be the target crosssection at 3R/2 to result
in an equal signal strength at the Radar? ' a) 90m2 b) 270W/m2 c) 310m2 c1)30W/m2 71 The electric ﬁeld intensity at a distance of 10km from an antenna having a directive
gain of 10dB and radiating a total power of 60kW is 3) 06V/m b) 1.2V/m c) 0.36V/m d) 13.3}1W/m2 Electronics and Communication Engineering I a  SETA 7 INDIAN SPACE RESEARCH ORGANISATION‘W 7’ " I” 77"‘1‘46—5F77'1 8 ELECTRONICS AND COMMUNICATION ENGINEERING 72 What is the characteristic impedance of a coaxial transmission line having inner
conductor radius of 1mm, outer conductor radius of 2mm and dielectric constant of
4.0? a) 50 ohm ' b) 60 ohm c) 20.62 ohm ‘ d) none 73 An impedance of 10 — j2 ohms is connected to another impedance of 45 + j5 ohms
through a transmission line having a characteristic impedance of 50 ohms. Assess the
stability Of thiscircuit. a) Highly stable
» b) Stability cannot be determined from the given information
c) Highly unstable d) Marginally unstable 74 A transmission line of characteristic impedance 75 ohms is terminated with an
impedance of 50 ohms. The line length is increased from zero. What will be the locus of the input impedance at the other end of the line? (NB. 2 Reference impedance of
Smith Chart = 50 Ohms) I: ..._
I we! 9%???
.‘%¢:\o‘35%9
* °’‘B ‘ 3) Locus [A] 10) Locus [B] c) Locus [C]  d) Locus [D] 75 The value of the integral f sin z/z3 . dz around the circle z=2 is
a) l b) 0  c) —1/2 d) 1/z Electronics and Communication Engineering SETA 76 77 78 Page:
WiﬁiJJZOF 18
ELECTRONICS AND COMMUNICATION ENGINEERING INDIAN SPACE RESEARCH ORGANISATION Which of the following functions have a jump discontinuity at x=0 agoranI Iaan=lkz
{sin(x) x i 0 d) None of the above
c) x ’ I
0, x = 0 What would be the output of the following circuit, if a positive going unipolar pulse with an amplitude greater than Vref, is applied at the input?
 7 R2 a) V0 will go high momentarily and return to low
b) Vo will go low momentarily and return to high
c) Vo will go high and remain high d) Vo will not change its previous state What is the output voltage across the 900 ohm load in the circuit given below? 5005 1K 900 a) 10V b) 14.67V _ c) 20V d) 9.47 V Electronics and Communication Engineering SETA 7 7 VINPIAN SPACE RE$EARC_ll ORGANISATION“, » 1~8—oe= *1 8 79 What is the transfer function of the network given below? 1
M T;
V1
1 V2
:0
a) (s + 1)/(2s + 1) b)1/(1+s) c) 1/(2s + 1) d) 1/(s2 +25 + 1) 80 A voltage regulator having Vref=1.25V needs to generate 5V output. Assume that Iadj = IOOuA and R1 = 10kohm. What should be value of R2?
U1 ‘ a) 30 kohm b) 33.33 kohm c) 16.66kohm d) 22.22 kohm Electronics and Communication Engineering IE. SETA ...
View
Full Document
 Spring '07
 Subramanian

Click to edit the document details