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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 PYQ2021Digital CircuitsNumber RepresentationsMCQ · 1 mark
​​​​​​​If (1235)x = (3033)y(1235)_{x}\:=\:(3033)_{y}, where xx and yy indicate the bases of the corresponding numbers, then
Official PYQ2021Digital CircuitsCombinatorial CircuitsMCQ · 1 mark
​​​​​​Addressing of a 32K × 1632K\:\times\:16 memory is realized using a single decoder. The minimum number of AND\text{AND} gates required for the decoder is
Official PYQ2021Control SystemsMCQ · 1 mark
The block diagram of a feedback control system is shown in the figure The transfer function Y(s)X(s)\dfrac{Y{\left ( s \right )}}{X {\left ( s \right )}} of the system is
Official PYQ2021Control SystemsMCQ · 1 mark
The complete Nyquist plot of the open-loop transfer function G(s)H(s)G(s)H(s) of a feedback control system in the figure. If G(s)H(s)G(s)H(s) has one zero in the right-half of the ss-plane, the number of poles that the closed-loop system will have in the right-half of the ss-plane is
Official PYQ2021ElectromagneticsPlane Waves and PropertiesMCQ · 1 mark
Consider a rectangular coordinate system (x,y,z)(x,y,z) with unit vectors ax aya_{x}\:a_{y} and aza_{z}. A plane wave traveling in the region z≥0z\geq 0 with electric field vector E=10cos⁡(2×108t + βz)ayE=10\cos\left ( 2\times 10^{8}t\:+\:\beta z\right )a_{y} is incident normally on the plane at z=0z=0, where β\beta is the phase constant. The region z≥0z\geq 0 is in free …
Official PYQ2021Engineering MathematicsLinear AlgebraNAT · 1 mark
If the vectors (1.0, −1.0, 2.0)(1.0,\:-1.0,\:2.0), (7.0, 3.0, x)(7.0,\:3.0,\:x) and (2.0, 3.0, 1.0)(2.0,\:3.0,\:1.0) in R3\mathbb{R}^{3} are linearly dependent, the value of xx is __________
Official PYQ2021Engineering MathematicsVector AnalysisNAT · 1 mark
Consider the vector field F = ax(4y−c1z)+ay(4x+2z)+az(2y+z)F\:=\:a_{x}\left ( 4y-c_{1}z \right )+a_y\left ( 4x + 2z\right )+a_{z}\left ( 2y +z\right ) in a rectangular coordinate system (x,y,z)(x,y,z) with unit vectors ax, aya_{x},\:a_{y} and aza_{z}. If the field FF is irrotational (conservative), then the constant c1c_{1} (in integer) is _________________
Official PYQ2021Networks, Signals and SystemsCircuit AnalysisNAT · 1 mark
Consider the circuit shown in the figure. The current II flowing through the 7 Ω7\:\Omega resistor between PP and QQ (rounded off to one decimal place) is ________ AA.
Official PYQ2021Networks, Signals and SystemsCircuit AnalysisNAT · 1 mark
Consider the circuit shown in the figure. The value of v0v_{0} (rounded off to one decimal place) is _________ VV.
Official PYQ2021Digital CircuitsData ConvertersNAT · 1 mark
An 88-bit unipolar (all analog output values are positive) digital-to-analog converter (DAC)\text{(DAC)} has a full-scale voltage range from 0  V0\; V to 7.68 V7.68\:V. If the digital input code is 1001011010010110 (the leftmost bit is MSB\text{MSB}), then the analog output voltage of the DAC\text{DAC} (rounded off to one decimal place) is ___________ VV.
Official PYQ2021CommunicationsRandom ProcessesNAT · 1 mark
The autocorrelation function RX(τ)R_{X}\left ( \tau \right ) of a wide-sense stationary random process X(t)X(t) is shown in the figure. The average power of X(t)X(t) is ________________
Official PYQ2021CommunicationsAnalog CommunicationsNAT · 1 mark
Consider a carrier signal which is amplitude modulated by a single-tone sinusoidal message signal with a modulation index of 50%50\%. If the carrier and one of the sidebands are suppressed in the modulated signal, the percentage of power saved (rounded off to one decimal place) is ______________
Official PYQ2021CommunicationsInformation TheoryNAT · 1 mark
A speech signal, band limited to 4 kHz4\:\text{kHz}, is sampled at 1.251.25 times the Nyquist rate. The speech samples, assumed to be statistically independent and uniformly distributed in the range −5 V-5\:V to +5 V+5\:V, are subsequently quantized in an 88-bit uniform quantizer and then transmitted over a voice-grade AWGN\text{AWGN} telephone channel. If …
Official PYQ2021CommunicationsDigital CommunicationsNAT · 1 mark
A 4 kHz4\:kHz sinusoidal message signal having amplitude 4 V4\:V is fed to a delta modulator (DMDM) operating at a sampling rate of 32 kHz32\:\text{kHz}. The minimum step size required to avoid slope overload noise in the DMDM (rounded off to two decimal places) is _____ VV.
Official PYQ2021ElectromagneticsTransmission LinesNAT · 1 mark
The refractive indices of the core and cladding of an optical fiber are 1.501.50 and 1.481.48, respectively. The critical propagation angle, which is defined as the maximum angle that the light beam makes with the axis of the optical fiber to achieve the total internal reflection, (rounded off to two decimal places) is _____ degree.
Official PYQ2021Engineering MathematicsComplex AnalysisMCQ · 2 marks
Consider the integral ∮csin(x)x2(x2+4)dx\oint _{c}\frac{sin\left ( x \right )}{x^{2}\left ( x^{2}+4 \right )}dx where CC is a counter-clockwise oriented circle defined as ∣x−i∣=2\left | x-i \right |=2. The value of the integral is
Official PYQ2021Engineering MathematicsProbability and StatisticsMCQ · 2 marks
A box contains the following three coins. A fair coin with head on one face and tail on the other face. A coin with heads on both the faces. A coin with tails on both the faces. A coin is picked randomly from the box and tossed. Out of the two remaining coins in the box, one coin is then picked randomly and tossed. If the first toss results in a head, the …
Official PYQ2021Networks, Signals and SystemsCircuit AnalysisMCQ · 2 marks
The switch in the circuit in the figure is in position PP for a long time and then moved to position QQ at time t=0t=0. The value of dv(t)dt\dfrac{dv\left ( t \right )}{dt} at t=0+t=0^{+} is
Official PYQ2021Networks, Signals and SystemsCircuit AnalysisMCQ · 2 marks
Consider the two-port network shown in the figure. The admittance parameters, in siemens, are
Official PYQ2021Analog CircuitsBJT and MOSFET AmplifiersMCQ · 2 marks
For an nn-channel silicon MOSFET\text{MOSFET} with 10 nm10\:nm gate oxide thickness, the substrate sensitivity (∂VT/∂∣VBS∣)\left ( \partial V_{T}/\partial \left | V_{BS} \right | \right ) is found to be 50 mV/V50\:mV/V at a substrate voltage ∣VBS∣=2V\left | V_{BS} \right |=2V, where VTV_{T} is the threshold voltage of the MOSFET\text{MOSFET}. Assume that, …