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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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20 on this page
Official PYQ2020Networks, Signals and SystemsLTI SystemsMCQ · 1 mark
The pole-zero map of a rational function G(s)G(s) is shown below. When the closed contour Γ\Gamma is mapped into the G(s)G(s)-plane, then the mapping encircles
Official PYQ2020CommunicationsDigital CommunicationsMCQ · 1 mark
A digital communication system transmits a block of NN bits. The probability of error in decoding a bit is α\alpha. The error event of each bit is independent of the error events of the other bits. The received block is declared erroneous if at least one of its bits is decoded wrongly. The probability that the received block erroneous is
Official PYQ2020ElectromagneticsTransmission LinesMCQ · 1 mark
The impedances Z=jX,Z=jX, for all XX in the range (−∞,∞)\left ( -\infty ,\infty \right ), map to the Smith chart as
Official PYQ2020Networks, Signals and SystemsLTI SystemsMCQ · 1 mark
Which one of the following pole-zero plots corresponds to the transfer function of an LTI\text{LTI} system characterized by the input-output difference equation given below? y[n]=∑k=03(−1)kx[n−k]y\left [ n \right ]=\sum ^{3}_{k=0}\left ( -1 \right )^{k}x\left [ n-k \right ]
Official PYQ2020Networks, Signals and SystemsCircuit AnalysisNAT · 1 mark
In the given circuit, the two-port network has the impedance matrix [Z]=[406060120]\begin{bmatrix} Z \end{bmatrix}=\begin{bmatrix} 40 & 60\\ 60& 120 \end{bmatrix}. The value of ZLZ_{L} for which maximum power is transferred to the load is _____________Ω\Omega.
Official PYQ2020Networks, Signals and SystemsCircuit AnalysisNAT · 1 mark
The current in the RL\text{RL}-circuit shown below is i(t)=10cos⁡(5t−π/4)Ai\left ( t \right )=10\cos\left ( 5t-\pi /4 \right )A. The value of the inductor (rounded off to two decimal places)\text{(rounded off to two decimal places)} is _______ H\text{H}.
Official PYQ2020Networks, Signals and SystemsCircuit AnalysisNAT · 1 mark
In the circuit shown below, all the components are ideal and the input voltage is sinusoidal. The magnitude of the steady-state output VoV_{o} ( rounded off to two decimal places) is ______ VV.
Official PYQ2020Analog CircuitsOp-amp CircuitsNAT · 1 mark
In the circuit shown below, all the components are ideal. If ViV_{i} is +2 V+2\:V, the current IoI_{o} sourced by the op-amp is __________ mA\text{mA}.
Official PYQ2020Digital CircuitsComputer OrganizationNAT · 1 mark
In an 80858085 microprocessor, the number of address lines required to access a 1616 K byte memory bank is ____________ .
Official PYQ2020Digital CircuitsData ConvertersNAT · 1 mark
A 1010-bit D/A converter is calibrated over the full range from 00 to 1010 V. If the input to the D/A converter is 13 A13 \:A (in hex), the output ( rounded off to three decimal places) is __________ VV.
Official PYQ2020ElectromagneticsTransmission LinesNAT · 1 mark
A transmission line of length 3λ/43\lambda /4 and having a characteristic impedance of 5050 Ω\Omega is terminated with a load of 400Ω400 \Omega. The impedance (rounded off to two decimal places) seen at the input end of the transmission line is __________ Ω\Omega.
Official PYQ2020CommunicationsInformation TheoryNAT · 1 mark
A binary random variable XX takes the value +2+2 or −2-2. The probability P(X=+2)=αP(X=+2)=\alpha. The value of α\alpha (rounded off to one decimal place), for which the entropy of XX is maximum, is __________.
Official PYQ2020Networks, Signals and SystemsLTI SystemsNAT · 1 mark
The loop transfer function of a negative feedback system is G(s)H(s)=K(s+11)s(s+2)(s+8).G\left ( s \right )H\left ( s \right )=\frac{K(s+11)}{s(s+2)(s+8)}. The value of KK, for which the system is marginally stable, is ___________.
Official PYQ2020Engineering MathematicsProbability and StatisticsNAT · 1 mark
The random variable Y=∫−∞∞W(t)ϕ(t)dt, where ϕ(t)={1;5≤t≤70;otherwiseY=\int_{-\infty }^{\infty }W\left ( t \right )\phi \left ( t \right )dt, \text{ where } \phi \left ( t \right )=\begin{cases} 1; & 5\leq t\leq 7 &\\ 0; & \text{otherwise} \end{cases} and W(t)W(t) is a real white Gaussian noise process with two-sided power spectral density SW(f)=3W/HzS_{W}\left ( f \right )=3 W/Hz, for all ff. …
Official PYQ2020Engineering MathematicsProbability and StatisticsNAT · 1 mark
The two sides of a fair coin are labelled as 00 to 11. The coin is tossed two times independently. Let MM and NN denote the labels corresponding to the outcomes of those tosses. For a random variable XX, defined as X=min(M,N)X = \text{min}(M, N), the expected value E(X)E(X) (rounded off to two decimal places) is ___________.
Official PYQ2020Engineering MathematicsLinear AlgebraMCQ · 2 marks
Consider the following system of linear equations. x1+2x2=b1;2x1+4x2=b2;3x1+7x2=b3;3x1+9x2=b4\begin{array}{llll} x_{1}+2x_{2}=b_{1} ; & 2x_{1}+4x_{2}=b_{2}; & 3x_{1}+7x_{2}=b_{3} ; & 3x_{1}+9x_{2}=b_{4} \end{array} Which one of the following conditions ensures that a solution exists for the above system?
Official PYQ2020Engineering MathematicsDifferential EquationsMCQ · 2 marks
Which one of the following options contains two solutions of the differential equation dydx=(y−1)x?\dfrac{\mathrm{d} y}{\mathrm{d} x}=\left ( y-1 \right )x?
Official PYQ2020Networks, Signals and SystemsCircuit AnalysisMCQ · 2 marks
The current II in the given network is
Official PYQ2020Networks, Signals and SystemsDiscrete-time SignalsMCQ · 2 marks
A finite duration discrete-time signal x[n]x[n] is obtained by sampling the continuous-time signal x(t)=cos⁡(200πt)x\left ( t \right )=\cos\left ( 200\pi t \right ) at sampling instants t=n/400,n=0,1,…,7.t=n/400, n=0, 1, \dots ,7. The 88-point discrete Fourier transform (DFT)\text{(DFT)} of x[n]x[n] is defined as …
Official PYQ2020Networks, Signals and SystemsCircuit AnalysisMCQ · 2 marks
For the given circuit, which one of the following is correct state equation?