GATE ECE 2016 Set 3
GATE ECE
1
The diodes D1 and D2 in the figure are ideal and the capacitors are identical. The product RC is very
large compared to the time period of the ac voltage. Assuming that the diodes do not breakdown in the
reverse bias, the output voltage V0 (in volt) at the steady state is__________.
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2
Consider the circuit shown in the figure. Assuming VBE1 = VEB2 = 0.7 volt, value of the dc voltage Vc2 (in volt) is _______
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3
In the astable multivibrator circuit shown in the figure, the frequency of oscillation (in kHz) at the output pin 3 is
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4
For the circuit shown in the figure, R1 = R2 = R3 = 1 Ω, L = 1 µH and C = 1 µF. If the input Vin = cos(106t) , then the overall voltage gain (Vout /Vin) of the circuit is __________.
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5
A wide sense stationary random process $$X(t)$$ passes through the $$LTI$$ system shown in the figure. If the autocorrelation function of $$X(t)$$ is $${R_x}\left( \tau \right),$$ then the autocorrelation function $${R_x}\left( \tau \right),$$ of the output $$Y(t)$$ is equal to
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6
The bit error probability of a memoryless binary symmetric channel is $${10^{ - 5}}$$. If $${10^{ - 5}}$$ bits are sent over this channel, then the probability that not more than one bit will be in error is ________________
7
An analog baseband signal, band limited to 100 Hz, is sampled at the Nyquist rate. The samples are quantized into four message symbols that occur independently with probabilities $${p_1}$$ = $${p_4}$$ = 0.125 and $${p_2}$$ =$${p_3}$$. The information rate (bits/sec) of the message source is ____________________
8
A binary baseband digital communication system employs the signal
$$$p\left( t \right) = \left\{ {\matrix{
{{1 \over {\sqrt {{T_s}} }},} & {0 \le t \le {T_s}} \cr
{0,} & {otherwise} \cr
} ,} \right.$$$
for transmission of bits. The graphical representation of the matched filter output y(t) for this signal will be
9
A voice-grade AWGN (additive white Gaussian noise) telephone channel has a bandwidth of 4.0 kHz and two-sided noise power spectral density $${\eta \over 2} = 2.5\, \times \,{10^{ - 5}}$$ Watt per Hz. If information at the rate of 52 kbps is to be transmitted over this channel with arbitrarily small bit error rate, then the minimum bit energy $${E_b}$$ (in mJ/bit) necessary is ________________
10
For a superheterodyne receiver, the intermediate frequency is 15 MHz and the local oscillator frequency
is 3.5 GHz. If the frequency of the received signal is greater than the local oscillator frequency, then
the image frequency (in MHz) is _________.
11
For the unity feedback control system shown in the figure, the open-loop transfer function G(s) is
given as $$G\left(s\right)\;=\;\frac2{s\left(s\;+\;1\right)}$$ .The steady state error ess due to a unit step input is
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12
The forward-path transfer function and the feedback-path transfer function of a single loop negative
feedback control system are given as $$G\left(s\right)=\frac{K\left(s+2\right)}{s^2+2s+2}$$ and H(s) = 1 respectively.If the variable parameter K is real positive, then the location of the breakaway point on the
root locus diagram of the system is_____________.
13
The block diagram of a feedback control system is shown in the figure. The overall closed-loop gain G of the system is
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14
The first two rows in the Routh table for the characteristic equation of a certain closed-loop control
system are given as
The range of K for which the system is stable is
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15
A second-order linear time-invariant system is described by the following state equations
$$$\eqalign{& {d \over {dt}}{x_1}\left( t \right) + 2{x_1}\left( t \right) = 3u\left( t \right) \cr
& {d \over {dt}}{x_2}\left( t \right) + {x_2}\left( t \right) = u\left( t \right) \cr} $$$
Where x1(t), then the system is
16
Following is the k-map of a Boolean function of five variable P, Q, R, S and X. The minimum for the function is
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17
For the circuit shown in the figure, the delays of NOR gates, multiplexers and inverters are 2 ns, 1.5 ns and 1 ns, respectively.
If all the inputs P, Q, R, S and T are applied at the same time instant,
the maximum propagation delay (in ns) of the circuit is ___________.
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18
The minimum number of 2-input NAND gates required to implement a 2-input XOR gate is
19
Consider an air-filled rectangular waveguide with dimensions a = 2.286cm and b = 1.016cm. At 10GHz operating frequency, the value of the propagation constant (per meter) of the corresponding propagation mode is _____________________
20
If a right-handed circularly polarized wave is incident normally on a plane perfect conductor, then the reflected wave will be
21
Faraday's law of electromagnetic induction is mathematically described by which one of the following equations?
22
Consider an air-filled rectangular waveguide with dimensions a = 2.286 cm and b = 1.016 cm. The increasing order of the cut-off frequencies for different modes is
23
A radar operating at 5 GHz uses a common antenna for transmission and reception. The antenna has a gain of 150 and is aligned for maximum directional radiation and reception to a target 1 km away having radar cross-section of 3m2. If it transmits 100 kW, then the received power (in $$\mu W$$) is ______ .
24
The injected excess electron concentration profile in the base region of an npn BJT, biased in the
active region, is linear, as shown in the figure. If the area of the emitter-base junction is 0.001 cm2, µn = 800 cm2/(V-s) in the base region and depletion layer widths are negligible, then the collector
current Ic (in mA) at room temperature is __________.
(Given: thermal voltage VT = 26 mV at room temperature, electronic charge q = $$1.6\times10^{-19}\;C$$ )
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25
Consider the charge profile shown in the figure. The resultant potential distribution is best
described by
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26
The figure shows the I-V characteristics of a solar cell illuminated uniformly with solar light of
power 100 mW/cm2. The solar cell has an area of 3 cm2 and a fill factor of 0.7. The maximum efficiency (in %) of the device is __________.
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27
The figure shows the band diagram of a Metal Oxide Semiconductor (MOS). The surface region of
this MOS is in
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28
Figures $${\rm I}$$ and $${\rm I}{\rm I}$$ show two MOS capacitor of unit area. The capacitor in Figure I has insulator materials X (of thickness t1 = 1 nm and dielectric constant $${\varepsilon _1}$$ = 4) and Y (of thickness t2 =3 nm and dielectric constant $${\varepsilon _2}$$ = 200). The capacitor in Figure $${\rm I}{\rm I}$$ has only insulator material X of thickness teq. If the capacitors are of equal capacitance, then the value of teq (in nm) is ______
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29
In the circuit shown in the figure, the channel length modulation of all transistors is non-zero $$\left( {\lambda \ne 0} \right)$$. Also all transistors operate in saturation and have negligible body effect. The ac small
signal voltage gain $$\left( {{V_0}/{V_{in}}} \right)$$ of the circuit is
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30
In the circuit shown in the figure, transistor M1 is in saturation and has transconductance
gm = 0.01 siemens. Ignoring internal parasitic capacitances and assuming the channel length
modulation $$\lambda $$ to be zero, the small signal input pole frequency (in kHz) is _____
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31
Consider a $$2 \times 2$$ square matrix $$A = \left[ {\matrix{
\sigma & x \cr
\omega & \sigma \cr
} } \right]$$
Where $$x$$ is unknown. If the eigenvalues of the matrix $$A$$ are $$\left( {\sigma + j\omega } \right)$$ and $$\left( {\sigma - j\omega } \right)$$, then $$x$$ is equal to
Where $$x$$ is unknown. If the eigenvalues of the matrix $$A$$ are $$\left( {\sigma + j\omega } \right)$$ and $$\left( {\sigma - j\omega } \right)$$, then $$x$$ is equal to
32
If the vectors $${e_1} = \left( {1,0,2} \right),\,{e_2} = \left( {0,1,0} \right)$$ and $${e_3} = \left( { - 2,0,1} \right)$$ form an orthogonal basis of the three dimensional real space $${R^3},$$ then the vectors $$u = \left( {4,3, - 3} \right) \in {R^3}$$ can be expressed as
33
The integral $$\int\limits_0^1 {{{dx} \over {\sqrt {\left( {1 - x} \right)} }}} $$ is equal ________.
34
A triangle in the $$xy-$$plane is bounded by the straight lines $$2x=3y, y=0$$ and $$x=3.$$ The volume above the triangle and under the plane $$x+y+z=6Z$$ is ________.
35
The probability of getting a ''head'' in a single toss of a biased coin is $$0.3.$$ The coin is tossed repeatedly till a ''head'' is obtained. If the tosses are independent, then the probability of getting ''head'' for the first time in the fifth toss is ________.
36
The particular solution of the initial value problem given below is $$\,\,{{{d^2}y} \over {d{x^2}}} + 12{{dy} \over {dx}} + 36y = 0\,\,$$ with $$\,y\left( 0 \right) = 3\,\,$$ and $$\,\,{\left. {{{dy} \over {dx}}} \right|_{x = 0}} = - 36\,\,$$
37
Consider the first order initial value problem $$\,y' = y + 2x - {x^2},\,\,y\left( 0 \right) = 1,\,\left( {0 \le x < \infty } \right)$$ With exact solution $$y\left( x \right)\,\, = \,\,{x^2} + {e^x}.\,\,$$ For $$x=0.1,$$ the percentage difference between the exact solution and the solution obtained using a single iteration of the second-order Runge-Kutta method with step-size $$h=0.1$$ is __________.
38
The value of the integral $${1 \over {2\pi j}}\oint\limits_C {{{{e^z}} \over {z - 2}}dz} $$ along a closed contour $$c$$ in anti-clockwise direction for
(i) the point $${z_0} = 2$$ inside the contour $$c,$$ and
(ii) the point $${z_0} = 2$$ outside the contour $$c,$$ respectively, are
(i) the point $${z_0} = 2$$ inside the contour $$c,$$ and
(ii) the point $${z_0} = 2$$ outside the contour $$c,$$ respectively, are
39
For $$f\left( z \right) = {{\sin \left( z \right)} \over {{z^2}}},$$ the residue of the pole at $$z=0$$ ________.
40
In an 8085 microprocessor, the contents of the accumulator and the carry flag are A7 (in hex) and 0, respectively. If the instruction RLC is executed, then the contents of the accumulator (in hex) and the carry flag, respectively, will be
41
In the $$RLC$$ circuit shown in the figure, the input voltage is given by vi(t) = 2 cos(200t)+4 sin(500t). The output voltage v0(t) is
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42
The z-parameter matrix for the two-port network shown is $$$\left[ {\matrix{
{2\,j\,\omega } & {j\,\omega } \cr
{j\,\omega } & {3\, + \,2\,j\,\omega } \cr
} } \right]$$$
Where the entries are in $$\Omega $$. Suppose $$\,{Z_b}\,\left( {j\,\omega } \right) = {R_b} + j\,\omega $$
Then the value of $${R_b}$$ (in $$\Omega $$) equals _______________________3
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43
The z-parameter matrix $$\begin{bmatrix}z_{11}&z_{12}\\z_{21}&z_{22}\end{bmatrix}$$ for the two-port network shown is
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44
Assume that the circuit in the figure has reached the steady state before time t = 0 when the
3 Ω
resistor suddenly burns out, resulting in an open circuit. The current i(t) (in ampere) at t = 0+ is ____________.
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45
In the figure shown, the current i (in ampere) is ______.
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46
A continuous-time speech signal $${x_a}(t)$$ is sampled at a rate of 8 kHz and the samples are subsequently grouped in
blocks, each of size N. The DFT of each block is to be computed in real time using the radix-2 decimation-in-frequency
FFT algorithm. If the processor performs all operations sequentially, and takes 20 µs for computing each complex multiplication (including multiplications by 1 and −1) and the time required for addition/ subtraction is negligible, then the
maximum value of N is __________.
47
A discrete-time signal$$x\left[ n \right]\, = \delta \left[ {n - 3} \right]\, + 2\delta \left[ {n - 5} \right]$$ has z-transform x(z). If Y (z)=X (-z) is the z-transform of another signal y$$\left[ n \right]$$, then
48
The ROC (region of convergence) of the z-transform of a discrete-time signal is represented by the shaded
region in the z-plane. If the signal $$x\left[ n \right] = \,{\left( {2.0} \right)^{\left| n \right|}}$$ , $$ - \infty < n < + \infty $$ then the ROC of its z-transform is
represented by
49
Consider the signal $$\,x\left( t \right)$$ $$\,\,\, = \,\,\,\cos \left( {6\pi t} \right)\,\, + \,\,\sin \left( {8\pi t} \right),$$ where $$\,t$$ is in seconds. The Nyquist sampling rate (in samples/second) for the signal $$y\left( t \right)\, = x\,\,\left( {2t + 5} \right)$$ is
50
The direct form structure of an FIR (finite impulse response) filter is shown in the figure.
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The filter can be used to approximate a
51
If the signal x(t) = $${{\sin (t)} \over {\pi t}}*{{\sin (t)} \over {\pi t}}$$ with * denoting the convolution operation, then x(t) is equal to
General Aptitude
1
The number that least fits this set: (324, 441, 97 and 64) is ________.
2
It takes 10 s and 15 s, respectively, for two trains traveling at different constant speeds to completely pass
a telegraph post. The length of the first train is 120 m and that of the second train is 150 m. The
magnitude of the difference in the speeds of the two trains (in m/s) is ____________.