GATE EC 2022: Electronics and Communication Engineering
Text of page 1
GATE 2022 General Aptitude (GA)
Q.1 – Q.5 Carry ONE mark each.
Q.1 Mr. X speaks _________ Japanese _________ Chinese.
(A) neither / or
(B) either / nor
(C) neither / nor
(D) also / but
Q.2 A sum of money is to be distributed among P, Q, R, and S in the
proportion 5 : 2 : 4 : 3, respectively.
If R gets ₹ 1000 more than S, what is the share of Q (in ₹)?
(A) 500
(B) 1000
(C) 1500
(D) 2000
Page 1
Text of page 2
Q.3 A trapezium has vertices marked as P, Q, R and S (in that order anticlockwise).
The side PQ is parallel to side SR.
Further, it is given that, PQ = 11 cm, QR = 4 cm, RS = 6 cm and SP = 3 cm.
What is the shortest distance between PQ and SR (in cm)?
(A) 1.80
(B) 2.40
(C) 4.20
(D) 5.76
Page 2
Text of page 3
Q.4 The figure shows a grid formed by a collection of unit squares. The unshaded
unit square in the grid represents a hole.
What is the maximum number of squares without a “hole in the interior” that
can be formed within the 4 × 4 grid using the unit squares as building blocks?
(A) 15
(B) 20
(C) 21
(D) 26
Page 3
Text of page 4
Q.5 An art gallery engages a security guard to ensure that the items displayed are
protected. The diagram below represents the plan of the gallery where the
boundary walls are opaque. The location the security guard posted is identified
such that all the inner space (shaded region in the plan) of the gallery is within
the line of sight of the security guard.
If the security guard does not move around the posted location and has a 360o
view, which one of the following correctly represents the set of ALL possible
locations among the locations P, Q, R and S, where the security guard can be
posted to watch over the entire inner space of the gallery.
(A) P and Q
(B) Q
(C) Q and S
(D) R and S
Page 4
Text of page 5
Q. 6 – Q. 10 Carry TWO marks each.
Q.6 Mosquitoes pose a threat to human health. Controlling mosquitoes using
chemicals may have undesired consequences. In Florida, authorities have used
genetically modified mosquitoes to control the overall mosquito population. It
remains to be seen if this novel approach has unforeseen consequences.
Which one of the following is the correct logical inference based on the
information in the above passage?
(A) Using chemicals to kill mosquitoes is better than using genetically modified
mosquitoes because genetic engineering is dangerous
(B) Using genetically modified mosquitoes is better than using chemicals to kill
mosquitoes because they do not have any side effects
(C) Both using genetically modified mosquitoes and chemicals have undesired
consequences and can be dangerous
(D) Using chemicals to kill mosquitoes may have undesired consequences but it is
not clear if using genetically modified mosquitoes has any negative
consequence
Page 5
Text of page 6
Consider the following inequalities.
Q.7
(i) 2x − 1 > 7
(ii) 2x − 9 < 1
Which one of the following expressions below satisfies the above two
inequalities?
(A) x ≤ −4
(B) −4 < x ≤ 4
(C) 4 < x < 5
(D) x ≥ 5
Four points P(0, 1), Q(0, −3), R(−2, −1), and S(2, −1) represent the vertices
Q.8
of a quadrilateral.
What is the area enclosed by the quadrilateral?
(A) 4
(B) 4 2
(C) 8
(D) 8√2
Page 6
Text of page 7
Q.9 In a class of five students P, Q, R, S and T, only one student is known to have
copied in the exam. The disciplinary committee has investigated the situation
and recorded the statements from the students as given below.
Statement of P: R has copied in the exam.
Statement of Q: S has copied in the exam.
Statement of R: P did not copy in the exam.
Statement of S: Only one of us is telling the truth.
Statement of T: R is telling the truth.
The investigating team had authentic information that S never lies.
Based on the information given above, the person who has copied in the exam is
(A) R
(B) P
(C) Q
(D) T
Page 7
Text of page 8
Q.10 Consider the following square with the four corners and the
center marked as P, Q, R, S and T respectively.
Let X, Y and Z represent the following operations:
X: rotation of the square by 180 degree with respect to the
S-Q axis.
Y: rotation of the square by 180 degree with respect to the P-R axis.
Z: rotation of the square by 90 degree clockwise with respect to the axis
perpendicular, going into the screen and passing through the point T.
Consider the following three distinct sequences of operation (which are applied
in the left to right order).
(1) XYZZ
(2) XY
(3) ZZZZ
Which one of the following statements is correct as per the information
provided above?
(A) The sequence of operations (1) and (2) are equivalent
(B) The sequence of operations (1) and (3) are equivalent
(C) The sequence of operations (2) and (3) are equivalent
(D) The sequence of operations (1), (2) and (3) are equivalent
Page 8
Text of page 9
GATE 2022 Electronics and Communications Engineering (EC)
Q.11 – Q.35 Carry ONE mark Each
Q.11 Consider the two-dimensional vector field F⃗ (x, y) = x ı⃗ + y ȷ⃗, where ı⃗ and ȷ⃗ denote
the unit vectors along the x-axis and the y-axis, respectively. A contour C in the x-
y plane, as shown in the figure, is composed of two horizontal lines connected at the
two ends by two semicircular arcs of unit radius. The contour is traversed in the
counter-clockwise sense. The value of the closed path integral
F⃗ (x, y) ⋅ (dx ı⃗ + dy ȷ⃗ )
is _________.
(A) 0
(B) 1
(C) 8 + 2π
(D) −1
Page 9
Text of page 10
GATE 2022 Electronics and Communications Engineering (EC)
Q.12 Consider a system of linear equations Ax = b, where
1 −√2 3 1
A= , b= .
−1 √2 −3 3
This system of equations admits _________.
(A) a unique solution for x
(B) infinitely many solutions for x
(C) no solutions for x
(D) exactly two solutions for x
Page 10
Text of page 11
GATE 2022 Electronics and Communications Engineering (EC)
Q.13 The current I in the circuit shown is ________.
(A) 1.25 × 10 A
(B) 0.75 × 10 A
(C) −0.5 × 10 A
(D) 1.16 × 10 A
Page 11
Text of page 12
GATE 2022 Electronics and Communications Engineering (EC)
Q.14 Consider the circuit shown in the figure. The current I flowing through the 10 Ω
resistor is _________.
(A) 1A
(B) 0A
(C) 0.1 A
(D) -0.1 A
Page 12
Text of page 13
GATE 2022 Electronics and Communications Engineering (EC)
Q.15 The Fourier transform X(jω) of the signal
t
x (t) =
(1 + t )
is _________.
(A) π
ωe | |
2j
(B) π
ωe | |
2
(C) π | |
e
2j
(D) π | |
e
2
Page 13
Text of page 14
GATE 2022 Electronics and Communications Engineering (EC)
Q.16 Consider a long rectangular bar of direct bandgap p-type semiconductor. The
equilibrium hole density is 10 cm3 and the intrinsic carrier concentration is
10 cm3 . Electron and hole diffusion lengths are 2 μm and 1 μm, respectively.
The left side of the bar (x = 0) is uniformly illuminated with a laser having photon
energy greater than the bandgap of the semiconductor. Excess electron-hole pairs
are generated ONLY at x = 0 because of the laser. The steady state electron density
at x = 0 is 10 cm3 due to laser illumination. Under these conditions and ignoring
electric field, the closest approximation (among the given options) of the steady state
electron density at x = 2 μm, is ___________ .
(A) 0.37 × 10 cm3
(B) 0.63 × 10 cm3
(C) 3.7 × 10 cm3
(D) 10 cm3
Page 14
Text of page 15
GATE 2022 Electronics and Communications Engineering (EC)
Q.17 In a non-degenerate bulk semiconductor with electron density n = 10 cm3 , the
value of E − E = 200 meV, where E and E denote the bottom of the
conduction band energy and electron Fermi level energy, respectively. Assume
thermal voltage as 26 meV and the intrinsic carrier concentration is 10 cm3 . For
n = 0.5 × 10 cm3 , the closest approximation of the value of (E − E ), among
the given options, is __________.
(A) 226 meV
(B) 174 meV
(C) 218 meV
(D) 182 meV
Page 15
Text of page 16
GATE 2022 Electronics and Communications Engineering (EC)
Q.18 Consider the CMOS circuit shown in the figure (substrates are connected to their
respective sources). The gate width (W) to gate length (L) ratios of the
transistors are as shown. Both the transistors have the same gate oxide capacitance
per unit area. For the pMOSFET, the threshold voltage is 1 V and the mobility of
cm2
holes is 40 . For the nMOSFET, the threshold voltage is 1 V and the mobility
V.s
cm2
of electrons is 300 . The steady state output voltage V is ________.
V.s
(A) equal to 0 V
(B) more than 2 V
(C) less than 2 V
(D) equal to 2 V
Page 16
Text of page 17
GATE 2022 Electronics and Communications Engineering (EC)
Q.19 Consider the 2-bit multiplexer (MUX) shown in the figure. For OUTPUT to be the
XOR of C and D, the values for A , A , A , and A are ____________.
(A) A = 0, A = 0, A = 1, A = 1
(B) A = 1, A = 0, A = 1, A = 0
(C) A = 0, A = 1, A = 1, A = 0
(D) A = 1, A = 1, A = 0, A = 0
Page 17
Text of page 18
GATE 2022 Electronics and Communications Engineering (EC)
Q.20 The ideal long channel nMOSFET and pMOSFET devices shown in the circuits
have threshold voltages of 1 V and −1 V, respectively. The MOSFET substrates are
connected to their respective sources. Ignore leakage currents and assume that the
capacitors are initially discharged. For the applied voltages as shown, the steady
state voltages are _________________.
(A) V = 5 V, V =5V
(B) V = 5 V, V =4V
(C) V = 4 V, V =5V
(D) V = 4 V, V = −5 V
Page 18
Text of page 19
GATE 2022 Electronics and Communications Engineering (EC)
Q.21 Consider a closed-loop control system with unity negative feedback and KG(s) in
the forward path, where the gain K = 2. The complete Nyquist plot of the transfer
function G(s) is shown in the figure. Note that the Nyquist contour has been chosen
to have the clockwise sense. Assume G(s) has no poles on the closed right-half of
the complex plane. The number of poles of the closed-loop transfer function in the
closed right-half of the complex plane is ___________.
(A) 0
(B) 1
(C) 2
(D) 3
Page 19
Text of page 20
GATE 2022 Electronics and Communications Engineering (EC)
Q.22 The root-locus plot of a closed-loop system with unity negative feedback and
transfer function KG(s) in the forward path is shown in the figure. Note that K is
varied from 0 to ∞.
Select the transfer function G(s) that results in the root-locus plot of the closed-loop
system as shown in the figure.
(A) 1
G(s) =
(s + 1)
(B) 1
G(s) =
s +1
(C) s−1
G(s) =
(s + 1)
(D) s+1
G(s) =
s +1
Page 20
Text of page 21
GATE 2022 Electronics and Communications Engineering (EC)
Q.23 The frequency response H(f) of a linear time-invariant system has magnitude as
shown in the figure.
Statement I: The system is necessarily a pure delay system for inputs which are
bandlimited to −α ≤ f ≤ α.
Statement II: For any wide-sense stationary input process with power spectral
density S (f), the output power spectral density S (f) obeys S (f ) = S (f) for
−α ≤ f ≤ α.
Which one of the following combinations is true?
(A) Statement I is correct, Statement II is correct
(B) Statement I is correct, Statement II is incorrect
(C) Statement I is incorrect, Statement II is correct
(D) Statement I is incorrect, Statement II is incorrect
Page 21
Text of page 22
GATE 2022 Electronics and Communications Engineering (EC)
Q.24 In a circuit, there is a series connection of an ideal resistor and an ideal capacitor.
The conduction current (in Amperes) through the resistor is 2sin(t + π/2).
The displacement current (in Amperes) through the capacitor is _________.
(A) 2sin(t)
(B) 2sin(t + π)
(C) 2sin(t + π/2)
(D) 0
Page 22
Text of page 23
GATE 2022 Electronics and Communications Engineering (EC)
Q.25 Consider the following partial differential equation (PDE)
∂ f(x, y) ∂ f(x, y)
a +b = f(x, y),
∂x ∂y
where a and b are distinct positive real numbers. Select the combination(s) of values
of the real parameters ξ and η such that f(x, y) = e ( )
is a solution of the
given PDE.
(A) 1 1
ξ= , η=
√2a √2b
(B) 1
ξ= , η=0
√a
(C) ξ =0, η =0
(D) 1 1
ξ= , η=
√a √b
Page 23
Text of page 24
GATE 2022 Electronics and Communications Engineering (EC)
Q.26 An ideal OPAMP circuit with a sinusoidal input is shown in the figure. The 3 dB
frequency is the frequency at which the magnitude of the voltage gain decreases by
3 dB from the maximum value. Which of the options is/are correct?
(A) The circuit is a low pass filter.
(B) The circuit is a high pass filter.
(C) The 3 dB frequency is 1000 rad/s.
(D) The 3 dB frequency is rad/s.
Page 24
Text of page 25
GATE 2022 Electronics and Communications Engineering (EC)
Q.27 Select the Boolean function(s) equivalent to x + yz, where x, y, and z are Boolean
variables, and + denotes logical OR operation.
(A) x + z + xy
(B) (x + y)(x + z)
(C) x + xy + yz
(D) x + xz + xy
Q.28 Select the correct statement(s) regarding CMOS implementation of NOT gates.
(A) Noise Margin High (NM ) is always equal to the Noise Margin Low (NM ),
irrespective of the sizing of transistors.
(B) Dynamic power consumption during switching is zero.
(C) For a logical high input under steady state, the nMOSFET is in the linear regime of
operation.
(D) Mobility of electrons never influences the switching speed of the NOT gate.
Page 25
Text of page 26
GATE 2022 Electronics and Communications Engineering (EC)
Q.29 Let H(X) denote the entropy of a discrete random variable X taking K possible
distinct real values. Which of the following statements is/are necessarily true?
(A) H (X) ≤ log K bits
(B) H(X) ≤ H(2X)
(C) H (X) ≤ H(X )
(D) H (X) ≤ H(2 )
Q.30 Consider the following wave equation,
∂ f(x, t) ∂ f(x, t)
= 10000
∂t ∂x
Which of the given options is/are solution(s) to the given wave equation?
(A) f(x, t) = e ( )
+e ( )
(B) f(x, t) = e ( )
+ 0.5e ( )
(C) f(x, t) = e ( )
+ sin(x + 100t)
(D) f(x, t) = e ( )
+e ( )
Page 26
Text of page 27
GATE 2022 Electronics and Communications Engineering (EC)
Q.31 The bar graph shows the frequency of the number of wickets taken in a match by a
bowler in her career. For example, in 17 of her matches, the bowler has taken 5
wickets each. The median number of wickets taken by the bowler in a match
is __________ (rounded off to one decimal place).
Page 27
Text of page 28
GATE 2022 Electronics and Communications Engineering (EC)
Q.32 A simple closed path C in the complex plane is shown in the figure. If
2
dz = −iπA,
z −1
where i = √−1, then the value of A is ______ (rounded off to two decimal places).
Q.33 Let x (t) = e u(t) and x (t) = u(t) − u(t − 2), where u(⋅) denotes the unit step
function.
If y(t) denotes the convolution of x (t) and x (t), then lim y(t) = _________
→
(rounded off to one decimal place).
Page 28
Text of page 29
GATE 2022 Electronics and Communications Engineering (EC)
Q.34 An ideal MOS capacitor (p-type semiconductor) is shown in the figure. The MOS
capacitor is under strong inversion with V = 2 V. The corresponding inversion
charge density (Q ) is 2.2 μC/cm2 . Assume oxide capacitance per unit area as
C = 1.7 μF/cm2 . For V = 4 V, the value of Q is ______ μC/cm2 (rounded off
to one decimal place).
Q.35 A symbol stream contains alternate QPSK and 16-QAM symbols. If symbols from
this stream are transmitted at the rate of 1 mega-symbols per second, the raw
(uncoded) data rate is _______ mega-bits per second (rounded off to one decimal
place).
Page 29
Text of page 30
GATE 2022 Electronics and Communications Engineering (EC)
Q.36 – Q.65 Carry TWO marks Each
Q.36 The function f(x) = 8 log x − x + 3 attains its minimum over the interval
[1, e] at x = _________.
(Here log x is the natural logarithm of x.)
(A) 2
(B) 1
(C) e
(D) 1+e
2
Q.37 Let α, β be two non-zero real numbers and v , v be two non-zero real vectors of
size 3 × 1. Suppose that v and v satisfy v v = 0, v v = 1, and
v v = 1. Let A be the 3 × 3 matrix given by:
A = αv v + βv v
The eigenvalues of A are __________.
(A) 0, α, β
(B) 0, α + β, α − β
(C) α+β
0, , αβ
2
(D) 0, 0, α +β
Page 30
Text of page 31
GATE 2022 Electronics and Communications Engineering (EC)
Q.38 For the circuit shown, the locus of the impedance Z(jω) is plotted as ω increases
from zero to infinity. The values of R and R are:
(A) R = 2 kΩ, R = 3 kΩ
(B) R = 5 kΩ, R = 2 kΩ
(C) R = 5 kΩ, R = 2.5 kΩ
(D) R = 2 kΩ, R = 5 kΩ
Page 31
Text of page 32
GATE 2022 Electronics and Communications Engineering (EC)
Q.39 Consider the circuit shown in the figure with input V(t) in volts. The sinusoidal
steady state current I(t) flowing through the circuit is shown graphically (where t is
in seconds). The circuit element Z can be ________.
(A) a capacitor of 1 F
(B) an inductor of 1 H
(C) a capacitor of √3 F
(D) an inductor of √3 H
Page 32
Text of page 33
GATE 2022 Electronics and Communications Engineering (EC)
Q.40 Consider an ideal long channel nMOSFET (enhancement-mode) with gate length
10 µm and width 100 µm. The product of electron mobility (µ ) and oxide
capacitance per unit area (C ) is µ C = 1 mA/V 2 . The threshold voltage of the
transistor is 1 V. For a gate-to-source voltage V = [2 − sin(2t )] V and drain-to-
source voltage V = 1 V (substrate connected to the source), the maximum value
of the drain-to-source current is ________.
(A) 40 mA
(B) 20 mA
(C) 15 mA
(D) 5 mA
Page 33
Text of page 34
GATE 2022 Electronics and Communications Engineering (EC)
Q.41 For the following circuit with an ideal OPAMP, the difference between the maximum
and the minimum values of the capacitor voltage (V ) is __________.
(A) 15 V
(B) 27 V
(C) 13 V
(D) 14 V
Page 34
Text of page 35
GATE 2022 Electronics and Communications Engineering (EC)
Q.42 A circuit with an ideal OPAMP is shown. The Bode plot for the magnitude (in dB)
of the gain transfer function (A (jω) = V (jω)/V (jω)) of the circuit is also
provided (here, ω is the angular frequency in rad/s). The values of R and C are
____________.
(A) R = 3 kΩ, C = 1 μF
(B) R = 1 kΩ, C = 3 μF
(C) R = 4 kΩ, C = 1 μF
(D) R = 3 kΩ, C = 2 μF
Page 35
Text of page 36
GATE 2022 Electronics and Communications Engineering (EC)
Q.43 For the circuit shown, the clock frequency is f and the duty cycle is 25%. For the
signal at the Q output of the Flip-Flop, _______.
(A) frequency is f /4 and duty cycle is 50%
(B) frequency is f /4 and duty cycle is 25%
(C) frequency is f /2 and duty cycle is 50%
(D) frequency is f and duty cycle is 25%
Page 36
Text of page 37
GATE 2022 Electronics and Communications Engineering (EC)
Q.44 Consider an even polynomial p(s) given by
p(s) = s + 5s + 4 + K ,
where K is an unknown real parameter. The complete range of K for which p(s) has
all its roots on the imaginary axis is ________.
(A) 9
−4 ≤ K ≤
4
(B) 9
−3 ≤ K ≤
2
(C) 5
−6 ≤ K ≤
4
(D) −5 ≤ K ≤ 0
Page 37
Text of page 38
GATE 2022 Electronics and Communications Engineering (EC)
Q.45 Consider the following series:
n
c
For which of the following combinations of c, d values does this series converge?
(A) c = 1, d = −1
(B) c = 2, d = 1
(C) c = 0.5, d = −10
(D) c = 1, d = −2
Page 38
Text of page 39
GATE 2022 Electronics and Communications Engineering (EC)
Q.46 The outputs of four systems (S , S , S , and S ) corresponding to the input signal
sin(t), for all time t, are shown in the figure.
Based on the given information, which of the four systems is/are definitely NOT
LTI (linear and time-invariant)?
(A) S
(B) S
(C) S
(D) S
Page 39
Text of page 40
GATE 2022 Electronics and Communications Engineering (EC)
Q.47 Select the CORRECT statement(s) regarding semiconductor devices.
(A) Electrons and holes are of equal density in an intrinsic semiconductor at equilibrium.
(B) Collector region is generally more heavily doped than Base region in a BJT.
(C) Total current is spatially constant in a two terminal electronic device in dark under
steady state condition.
(D) Mobility of electrons always increases with temperature in Silicon beyond 300 K.
Page 40
Text of page 41
GATE 2022 Electronics and Communications Engineering (EC)
Q.48 A state transition diagram with states A, B, and C, and transition probabilities
p , p , … , p is shown in the figure (e.g., p denotes the probability of transition from
state A to B). For this state diagram, select the statement(s) which is/are universally
true.
(A) p +p =p +p
(B) p +p =p +p
(C) p +p +p =1
/(D) p +p +p =1
Page 41
Text of page 42
GATE 2022 Electronics and Communications Engineering (EC)
Q.49 Consider a Boolean gate (D) where the output Y is related to the inputs A and B as,
Y = A + B , where + denotes logical OR operation. The Boolean inputs ‘0’ and ‘1’
are also available separately. Using instances of only D gates and inputs ‘0’ and ‘1’,
__________ (select the correct option(s)).
(A) NAND logic can be implemented
(B) OR logic cannot be implemented
(C) NOR logic can be implemented
(D) AND logic cannot be implemented
Q.50 Two linear time-invariant systems with transfer functions
10 10
G (s) = and G (s) =
s +s+1 s + s√10 + 10
have unit step responses y (t) and y (t), respectively. Which of the following
statements is/are true?
(A) y (t) and y (t) have the same percentage peak overshoot.
(B) y (t) and y (t) have the same steady-state value.
(C) y (t) and y (t) have the same damped frequency of oscillation.
(D) y (t) and y (t) have the same 2% settling time.
Page 42
Text of page 43
GATE 2022 Electronics and Communications Engineering (EC)
Q.51 Consider an FM broadcast that employs the pre-emphasis filter with frequency
response
H (ω) = 1 + ,
where ω = 10 rad/sec.
For the network shown in the figure to act as a corresponding de-emphasis filter, the
appropriate pair(s) of (R, C) values is/are ________.
(A) R = 1 kΩ, C = 0.1 μF
(B) R = 2 kΩ, C = 1 μF
(C) R = 1 kΩ, C = 2 μF
(D) R = 2 kΩ, C = 0.5 μF
Page 43
Text of page 44
GATE 2022 Electronics and Communications Engineering (EC)
Q.52 A waveguide consists of two infinite parallel plates (perfect conductors) at a
separation of 10 cm, with air as the dielectric. Assume the speed of light in air to
be 3 × 10 m/s. The frequency/frequencies of TM waves which can propagate in
this waveguide is/are _______.
(A) 6 × 10 Hz
(B) 0.5 × 10 Hz
(C) 8 × 10 Hz
(D) 1 × 10 Hz
Page 44
Text of page 45
GATE 2022 Electronics and Communications Engineering (EC)
Q.53 The value of the integral
3(x + y )dxdy ,
where D is the shaded triangular region shown in the diagram, is _____ (rounded off
to the nearest integer).
Page 45
Text of page 46
GATE 2022 Electronics and Communications Engineering (EC)
Q.54 A linear 2-port network is shown in Fig. (a). An ideal DC voltage source of 10 V is
connected across Port 1. A variable resistance R is connected across Port 2. As R is
varied, the measured voltage and current at Port 2 is shown in Fig. (b) as a V versus
−I plot. Note that for V = 5 V, I = 0 mA, and for V = 4 V, I = −4 mA.
When the variable resistance R at Port 2 is replaced by the load shown in Fig. (c),
the current I is _______ mA (rounded off to one decimal place).
(a)
(b) (c)
Page 46
Text of page 47
GATE 2022 Electronics and Communications Engineering (EC)
Q.55 For a vector x = x[0], x[1], … , x[7] , the 8-point discrete Fourier transform (DFT)
is denoted by X = DFT (x) = X[0], X[1], … , X[7] , where
2π
X [k ] = x[n] exp −j nk .
8
Here, j = √−1. If x = [1, 0, 0, 0, 2, 0, 0, 0] and y = DFT DFT (x) , then the value
of y[0] is _________ (rounded off to one decimal place).
Q.56 A p-type semiconductor with zero electric field is under illumination (low level
injection) in steady state condition. Excess minority carrier density is zero at
x = ±2l , where l = 10 cm is the diffusion length of electrons. Assume
electronic charge, q = −1.6 × 10 C. The profiles of photo-generation rate of
carriers and the recombination rate of excess minority carriers (R) are shown. Under
these conditions, the magnitude of the current density due to the photo-generated
electrons at x = +2l is _________ mA/cm2 (rounded off to two decimal places).
Page 47
Text of page 48
GATE 2022 Electronics and Communications Engineering (EC)
Q.57 A circuit and the characteristics of the diode (D) in it are shown. The ratio of the
minimum to the maximum small signal voltage gain is ________ (rounded
off to two decimal places).
Q.58 Consider the circuit shown with an ideal OPAMP. The output voltage V is
__________V (rounded off to two decimal places).
Page 48
Text of page 49
GATE 2022 Electronics and Communications Engineering (EC)
Q.59 Consider the circuit shown with an ideal long channel nMOSFET (enhancement-
mode, substrate is connected to the source). The transistor is appropriately biased in
the saturation region with V and V such that it acts as a linear amplifier. v is the
small-signal ac input voltage. v and v represent the small-signal voltages at the
nodes A and B, respectively. The value of is ________ (rounded off to one
decimal place).
Q.60 The block diagram of a closed-loop control system is shown in the figure. R(s), Y(s),
and D(s) are the Laplace transforms of the time-domain signals r(t), y(t), and d(t),
respectively. Let the error signal be defined as e(t) = r(t) − y(t). Assuming the
reference input r(t ) = 0 for all t, the steady-state error e(∞), due to a unit step
disturbance d(t), is _________ (rounded off to two decimal places).
Page 49
Text of page 50
GATE 2022 Electronics and Communications Engineering (EC)
Q.61 The transition diagram of a discrete memoryless channel with three input symbols
and three output symbols is shown in the figure. The transition probabilities are as
marked.
The parameter α lies in the interval [0.25, 1]. The value of α for which the capacity
of this channel is maximized, is ________ (rounded off to two decimal places).
Q.62 Consider communication over a memoryless binary symmetric channel using a
(7, 4) Hamming code. Each transmitted bit is received correctly with probability
(1 − ε), and flipped with probability ε. For each codeword transmission, the receiver
performs minimum Hamming distance decoding, and correctly decodes the message
bits if and only if the channel introduces at most one bit error.
For ε = 0.1, the probability that a transmitted codeword is decoded correctly is
_________ (rounded off to two decimal places).
Page 50
Text of page 51
GATE 2022 Electronics and Communications Engineering (EC)
Q.63 Consider a channel over which either symbol x or symbol x is transmitted. Let the
output of the channel Y be the input to a maximum likelihood (ML) detector at the
receiver. The conditional probability density functions for Y given x and x are:
f | (y) = e ( )
u(y + 1),
f | (y) = e ( )
1 − u(y − 1) ,
where u(⋅) is the standard unit step function. The probability of symbol error for this
system is _________ (rounded off to two decimal places).
Q.64 Consider a real valued source whose samples are independent and identically
distributed random variables with the probability density function, f(x), as shown in
the figure.
Consider a 1 bit quantizer that maps positive samples to value α and others to value
β. If α ∗ and β ∗ are the respective choices for α and β that minimize the mean square
quantization error, then (α ∗ − β∗ ) = _________ (rounded off to two decimal places).
Page 51
Text of page 52
GATE 2022 Electronics and Communications Engineering (EC)
Q.65 In an electrostatic field, the electric displacement density vector, D⃗, is given by
D⃗ (x, y, z) = (x ı⃗ + y ȷ⃗ + xy k⃗ ) C/m2,
where ı⃗, ȷ⃗, k⃗ are the unit vectors along x-axis, y-axis, and z-axis, respectively.
Consider a cubical region R centered at the origin with each side of length 1 m, and
vertices at (±0.5 m, ±0.5 m, ±0.5 m). The electric charge enclosed within R is
_________ C (rounded off to two decimal places).
Page 52
Text of page 53
Q. No. Session Question Subject Key/Range Mark
Type Name
1 3 MCQ GA C 1
2 3 MCQ GA D 1
3 3 MCQ GA B 1
4 3 MCQ GA B 1
5 3 MCQ GA C 1
6 3 MCQ GA D 2
7 3 MCQ GA C 2
8 3 MCQ GA C 2
9 3 MCQ GA B 2
10 3 MCQ GA B 2
11 3 MCQ EC A 1
12 3 MCQ EC C 1
13 3 MCQ EC B 1
14 3 MCQ EC B 1
15 3 MCQ EC A 1
16 3 MCQ EC A 1
17 3 MCQ EC C 1
18 3 MCQ EC C 1
19 3 MCQ EC C 1
20 3 MCQ EC C 1
21 3 MCQ EC C 1
22 3 MCQ EC A 1
23 3 MCQ EC C 1
24 3 MCQ EC C 1
25 3 MSQ EC A,B 1
26 3 MSQ EC B,C 1
27 3 MSQ EC B,C 1
28 3 MSQ EC C 1
29 3 MSQ EC A,B,D 1
30 3 MSQ EC A,C 1
31 3 NAT EC 4.0 to 4.0 1
32 3 NAT EC 0.50 to 0.50 1
33 3 NAT EC 0.0 to 0.0 1
34 3 NAT EC 5.5 to 5.7 1
35 3 NAT EC 2.99 to 3.01 1
36 3 MCQ EC B 2
37 3 MCQ EC A 2
38 3 MCQ EC A 2
39 3 MCQ EC B 2
40 3 MCQ EC C 2
41 3 MCQ EC C 2
42 3 MCQ EC A 2
43 3 MCQ EC A 2
44 3 MCQ EC A 2
Text of page 54
45 3 MSQ EC B,D 2 46 3 MSQ EC C,D 2 47 3 MSQ EC A,C 2 48 3 MSQ EC A,C 2 49 3 MSQ EC A,C 2 50 3 MSQ EC A 2 51 3 MSQ EC A 2 52 3 MSQ EC MTA 2 53 3 NAT EC 512 to 512 2 54 3 NAT EC 3.9 to 4.1 2 55 3 NAT EC 7.9 to 8.1 2 56 3 NAT EC 0.57 to 0.61 2 57 3 NAT EC 0.70 to 0.80 2 58 3 NAT EC -0.55 to -0.45 2 59 3 NAT EC -2.1 to -1.9 2 60 3 NAT EC -0.11 to -0.09 2 61 3 NAT EC 1.00 to 1.00 2 62 3 NAT EC 0.84 to 0.86 2 63 3 NAT EC 0.22 to 0.25 2 64 3 NAT EC 1.15 to 1.18 2 65 3 NAT EC 0.48 to 0.52 2
Text of page 1
Q. No. Session Question Subject Key/Range Mark
Type Name
1 3 MCQ GA C 1
2 3 MCQ GA D 1
3 3 MCQ GA B 1
4 3 MCQ GA B 1
5 3 MCQ GA C 1
6 3 MCQ GA D 2
7 3 MCQ GA C 2
8 3 MCQ GA C 2
9 3 MCQ GA B 2
10 3 MCQ GA B 2
11 3 MCQ EC A 1
12 3 MCQ EC C 1
13 3 MCQ EC B 1
14 3 MCQ EC B 1
15 3 MCQ EC A 1
16 3 MCQ EC A 1
17 3 MCQ EC C 1
18 3 MCQ EC C 1
19 3 MCQ EC C 1
20 3 MCQ EC C 1
21 3 MCQ EC C 1
22 3 MCQ EC A 1
23 3 MCQ EC C 1
24 3 MCQ EC C 1
25 3 MSQ EC A,B 1
26 3 MSQ EC B,C 1
27 3 MSQ EC B,C 1
28 3 MSQ EC C 1
29 3 MSQ EC A,B,D 1
30 3 MSQ EC A,C 1
31 3 NAT EC 4.0 to 4.0 1
32 3 NAT EC 0.50 to 0.50 1
33 3 NAT EC 0.0 to 0.0 1
34 3 NAT EC 5.5 to 5.7 1
35 3 NAT EC 2.99 to 3.01 1
36 3 MCQ EC B 2
37 3 MCQ EC A 2
38 3 MCQ EC A 2
39 3 MCQ EC B 2
40 3 MCQ EC C 2
41 3 MCQ EC C 2
42 3 MCQ EC A 2
43 3 MCQ EC A 2
44 3 MCQ EC A 2
Text of page 2
45 3 MSQ EC B,D 2 46 3 MSQ EC C,D 2 47 3 MSQ EC A,C 2 48 3 MSQ EC A,C 2 49 3 MSQ EC A,C 2 50 3 MSQ EC A 2 51 3 MSQ EC A 2 52 3 MSQ EC MTA 2 53 3 NAT EC 512 to 512 2 54 3 NAT EC 3.9 to 4.1 2 55 3 NAT EC 7.9 to 8.1 2 56 3 NAT EC 0.57 to 0.61 2 57 3 NAT EC 0.70 to 0.80 2 58 3 NAT EC -0.55 to -0.45 2 59 3 NAT EC -2.1 to -1.9 2 60 3 NAT EC -0.11 to -0.09 2 61 3 NAT EC 1.00 to 1.00 2 62 3 NAT EC 0.84 to 0.86 2 63 3 NAT EC 0.22 to 0.25 2 64 3 NAT EC 1.15 to 1.18 2 65 3 NAT EC 0.48 to 0.52 2
Page 1 of 54
Source: GATE. Question paper published by GATE.