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GATE EC question library

Practise GATE EC Electronics and Communication previous year questions free. Browse by subject, syllabus topic, year and question type, with answers and available solutions.

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Official PYQ2014Digital CircuitsCombinatorial CircuitsMCQ · 2 marks
In the circuit shown, WW and YY are MSBs of the control inputs. The output FF is given by
Official PYQ2014Digital CircuitsCombinatorial CircuitsMCQ · 2 marks
If XX and YY are inputs and the Difference (D=X−Y)(D=X-Y) and the Borrow (B)(B) are the outputs, which one of the following diagrams implements a half-subtractor?
Official PYQ2014Networks, Signals and SystemsLTI SystemsNAT · 2 marks
Let H1(z)=(1−pz−1)−1,H2(z)=(1−qz−1)−1,H(z)=H1(z)+rH2(z).H_{1}(z)= (1-pz^{-1})^{-1},H_{2}(z)= (1-qz^{-1})^{-1},H(z)=H_{1}(z)+rH_{2}(z). The quantities p,p, qq, rr are real numbers. Consider p=12,q=−14,∣r∣<1.p=\frac{1}{2},q=-\frac{1}{4},\mid r \mid < 1. If the zero of H(z)H(z) lies on the unit circle, then rr == _________
Official PYQ2014Networks, Signals and SystemsLTI SystemsMCQ · 2 marks
Let h(t)h(t) denote the impulse response of a causal system with transfer function 1s+1.\frac{1}{s+1}. Consider the following three statements. S1S1: The system is stable. S2S2: h(t+1)h(t)\frac{h(t+1)}{h(t)} is independent of tt for t>0t > 0. S3S3: A non-causal system with the same transfer function is stable. For the above system,
Official PYQ2014Networks, Signals and SystemsDiscrete-time SignalsNAT · 2 marks
The zz-transform of the sequence x[n]x[n] is given by X(z)=1(1−2z−1)2,X(z)=\frac{1}{(1-2z^{-1})^{2}}, with the region of convergence ∣z∣>2\mid z \mid >2. Then, x[2]x[2] is _________.
Official PYQ2014Networks, Signals and SystemsLTI SystemsNAT · 2 marks
The steady state error of the system shown in the figure for a unit step input is _________.
Official PYQ2014Engineering MathematicsLinear AlgebraMCQ · 2 marks
The state equation of a second-order linear system is given by x˙(t)=Ax(t),        x(0)=x0\dot{x}(t)=Ax(t), \:\:\:\:\:\:\:\:x(0)=x_{0} For x0=[1−1],x_{0}= \begin{bmatrix} 1\\ -1 \end{bmatrix}, x(t)=[e−t−e−t],x(t)= \begin{bmatrix} e^{-t}\\ -e^{-t} \end{bmatrix}, and for x0=[01],x_{0}= \begin{bmatrix} 0\\ 1 \end{bmatrix}, x(t)[e−t−e−2t−e−t+2e−2t]x(t) \begin{bmatrix} e^{-t}-e^{-2t}\\ -e^{-t}+2e^{-2t} \end{bmatrix}. When …
Official PYQ2014Networks, Signals and SystemsLTI SystemsMCQ · 2 marks
In the root locus plot shown in the figure, the pole/zero marks and the arrows have been removed. Which one of the following transfer functions has this root locus?
Official PYQ2014CommunicationsRandom ProcessesMCQ · 2 marks
Let X(t)X(t) be a wide sense stationary (WSS)(WSS) random process with power spectral density SX(f).S_{X}(f). If Y(t)Y(t) is the process defined as Y(t)=X(2t−1)Y(t)= X(2t-1), the power spectral density SY(f)S_{Y}( f ) is
Official PYQ2014CommunicationsRandom ProcessesNAT · 2 marks
A real band-limited random process X(t)X(t) has two-sided power spectral density SX(f)={10−6(3000−∣f∣)Watts/Hzfor ∣f∣≤3kHz0otherwiseS_{X}(f)= \begin{cases} 10^{-6} (3000-\mid f \mid) \text{Watts/Hz} & \text{for } \mid f \mid \leq 3 kHz \\ 0 & \text{otherwise} \end{cases} where ff is the frequency expressed in Hz.The signal X(t)X(t) modulates a carrier cos⁡16000πt\cos16000\pi t and the resultant …
Official PYQ2014CommunicationsDigital CommunicationsNAT · 2 marks
In a PCMPCM system, the signal m(t)={sin⁡(100πt)+cos⁡(100πt)}Vm(t)=\left \{\sin(100\pi t)+\cos(100\pi t) \right \}V is sampled at the Nyquist rate. The samples are processed by a uniform quantizer with step size 0.750.75 VV. The minimum data rate of the PCMPCM system in bits per second is ______.
Official PYQ2014Engineering MathematicsProbability and StatisticsNAT · 2 marks
A binary random variable XX takes the value of 11 with probability 1/31/3. XX is input to a cascade of 22 independent identical binary symmetric channels (BSCs) each with crossover probability 1/21/2. The output of BSCs are the random variables Y1Y_{1} and Y2Y_{2} as shown in the figure. The value of H(Y1)+H(Y2)H( Y_{1} )+H( Y_{2} ) in bits is …
Official PYQ2014Engineering MathematicsVector AnalysisNAT · 2 marks
Given the vector A=(cos⁡x)(sin⁡y)ax^+(sin⁡x)(cos⁡y)ay^,\textbf{A}= ( \cos x ) ( \sin y )\hat{a_{x}}+( \sin x )( \cos y )\hat{a_{y}}, where ax^,\hat{a_{x}}, ay^\hat{a_{y}} denote unit vectors along xx, yy directions, respectively. The magnitude of curl of A\textbf{A} is __________
Official PYQ2014Digital CircuitsCombinatorial CircuitsMCQ · 2 marks
A region shown below contains a perfect conducting half-space and air. The surface current Ks→\overrightarrow{K_{s}} on the surface of the perfect conductor is Ks→=x^2\overrightarrow{K_{s}}= \hat{x}2 amperes per meter. The tangential H→\overrightarrow{H} field in the air just above the perfect conductor is
Official PYQ2014ElectromagneticsPlane Waves and PropertiesNAT · 2 marks
Assume that a plane wave in air with an electric field E→=10cos⁡(ωt−3x−3z)ay^V/m\overrightarrow{E}= 10\cos ( \omega t-3x-\sqrt{3}z )\hat{a_{y}}V/m is incident on a non-magnetic dielectric slab of relative permittivity 33 which covers the region z>0z > 0. The angle of transmission in the dielectric slab is _________ degrees.
Official PYQ2014General AptitudeMCQ · 1 mark
Which of the following options is the closest in meaning to the word underlined in the sentence below? In a democracy, everybody has the freedom to disagree with the government.
Official PYQ2014General AptitudeMCQ · 1 mark
After the discussion, Tom said to me, 'Please revert!'. He expects me to _________.
Official PYQ2014General AptitudeMCQ · 1 mark
While receiving the award, the scientist said, "I feel vindicated". Which of the following is closest in meaning to the word ‘vindicated’?
Official PYQ2014General AptitudeMCQ · 1 mark
Let f(x,y)=xnym=Pf(x,y)=x^n y^m=P. If xx is doubled and yy is halved, the new value of ff is
Official PYQ2014General AptitudeNAT · 1 mark
In a sequence of 1212 consecutive odd numbers, the sum of the first 55 numbers is 425425. What is the sum of the last 55 numbers in the sequence?