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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 PYQ2017Analog CircuitsBJT and MOSFET AmplifiersMCQ · 1 mark
For a narrow base PNP BJT , the excess minority carrier concentrations(ΔnE\Delta n_{E} for emitter,ΔpB\Delta p_{B} for base ,Δnc\Delta n_{c} for collector) normalized to equilibrium minority carrier concentrations(nE0n_{E0} for emitter, , ΔpB0\Delta p_{B0} for base ,ΔnC0\Delta n_{C0} for collector) in the quasi-neutral emitter,base and collector regions …
Official PYQ2017Analog CircuitsOp-amp CircuitsMCQ · 1 mark
For the operational amplifier circuit shown, the output saturation voltage are ±15 V\pm 15 \:V. The upper and lower threshold voltages for the circuit are,respectively,
Official PYQ2017Analog CircuitsBJT and MOSFET AmplifiersMCQ · 1 mark
A good transconductance amplifier should have
Official PYQ2017Analog CircuitsBJT and MOSFET AmplifiersMCQ · 1 mark
The Miller effect in the context of a Common Emitter amplifier explains
Official PYQ2017Digital CircuitsSequential CircuitsMCQ · 1 mark
In the latch circuit shown, the NANDNAND gates have non-zero, but unequal propagation delays. The present input condition is P=Q=’0’P=Q=’0’. If the input condition is changed simultaneously to P=Q=’1’P=Q=’1’, the outputs XX and YY are,
Official PYQ2017Digital CircuitsComputer OrganizationMCQ · 1 mark
The clock frequency of an 80858085 microprocessor is 55 MHz . If the time required to execute an instruction is 1.4 μs1.4 \: \mu s, then the number of T-states needed for executing the instruction is
Official PYQ2017Digital CircuitsSequential CircuitsNAT · 1 mark
Consider the D-Latch shown in the figure, which is transparent when its clock input CKCK is high and has zero propagation delay. In the figure , the clock signal CLKCLK has a 50%50 \% duty cycle and CLK2CLK2 is a one-fifth period delayed version of CLK1CLK1.The duty cycle at the output of the latch in percentage is _________.
Official PYQ2017Control SystemsNAT · 1 mark
The open loop transfer function G(s)=(s+1)sp(s+2)(s+3)G(s)=\frac{(s+1)}{s^{p}(s+2)(s+3)} where pp is an integer, is connected in unity feedback configuration as shown in figure. Given that the steady state error is zero for unit step input and is 66 for unit ramp input, the parameter pp is__________.
Official PYQ2017Control SystemsMCQ · 1 mark
Consider a stable system with transfer function,G(s)=sp+b1sp−1+⋯+bpsq+a1sq−1+⋯+aqG(s)=\frac{s^{p}+b_{1}s^{p-1}+\dots +b_{p}}{s^{q}+a_{1}s^{q-1}+\dots +a_{q}}, where b1,…,bpb_1, \dots ,b_p and a1,…,aqa_1, \dots ,a_q are real valued constants.The slope of the Bode log magnitude curve of G(s)G(s) converges to −60dB/decade-60 \text{dB/decade} as ω→∞ω\to \infty.A possible pair of values for pp and …
Official PYQ2017Analog CircuitsOp-amp CircuitsMCQ · 1 mark
Which of the following can be the pole-zero configuration of a phase-lag controller (lag compensator)?
Official PYQ2017CommunicationsInformation TheoryNAT · 1 mark
Let (X1,X2)\left ( X_{1},X_{2} \right ) be independent random variables. (X1)\left ( X_{1} \right ) has mean 00 and variance 11, while (X2)\left ( X_{2} \right ) has mean 11 and variance 44. The mutual information I(X1,X2)I\left (X_{1},X_{2} \right ) between X1X1 and X2X2 in bits is_______.
Official PYQ2017CommunicationsDigital CommunicationsMCQ · 1 mark
Which one of the following statements about differential pulse code modulation (DPCM) is true?
Official PYQ2017CommunicationsDigital CommunicationsMCQ · 1 mark
In a digital communication system, the overall pulse shape p(t)p(t) at the receiver before the sampler has the Fourier transform P(f)P(f). If the symbols are transmitted at the rate of 20002000 symbols per second, for which of the following cases is the inter symbol interference zero?
Official PYQ2017ElectromagneticsTransmission LinesNAT · 1 mark
The voltage of an electromagnetic wave propagating in a coaxial cable with uniform characteristic impedance is V(l)=e−γl+jωtV(l)= e^{-\gamma l +j\omega t } Volts, where ll is the distance along the length of the cable in meters, γ=(0.1+j40)m−1\gamma=(0.1+j40)m^{-1} is the complex propagation constant, and ω=2π×109\omega=2 \pi \times 10^{9} rad/s is the angular frequency. The …
Official PYQ2017ElectromagneticsTransmission LinesMCQ · 1 mark
Consider a wireless communication link between a transmitter and a receiver located in free space, with finite and strictly positive capacity. If the effective areas of the transmitter and the receiver antennas, and the distance between them are all doubled, and everything else remains unchanged , the maximum capacity of the wireless link
Official PYQ2017Engineering MathematicsCalculusMCQ · 2 marks
Let f(x)=ex+x2f(x)=e^{x+x^{2}} for real xx . From among the following, choose the Taylor series approximation of f(x)f(x) around x=0x=0, which includes all powers of xx less than or equal to 33.
Official PYQ2017Engineering MathematicsCalculusNAT · 2 marks
A three dimensional region RR of finite volume is described by x2+y2≤z3;  0≤z≤1,x^2 + y^2 \leq z^3; \: \: 0 \leq z \leq 1, where x,y,zx,y,z are real. The volume of RR (up to two decimal places) is _________
Official PYQ2017Engineering MathematicsCalculusNAT · 2 marks
Let I=∫c(2zdx+2ydy+2xdx)I=\int_{c}\left ( 2zdx+2ydy+2xdx \right ) where x,y,zx,y,z are real, and let CC be the straight line segment from point A:(0,2,1)A:(0,2,1) to point B:(4,1,−1)B:(4,1,-1).The value of II is ____________.
Official PYQ2017Engineering MathematicsDifferential EquationsMCQ · 2 marks
Which one of the following is the general solution of the first order differential equation dydx=(x+y−1)2,\frac{dy}{dx}=(x+y-1)^{2}, where x,yx,y are real?
Official PYQ2017Engineering MathematicsCalculusNAT · 2 marks
Starting with x=1x=1, the solution of the equation x3+x=1x^{3}+x=1, after two iterations of Newton-Raphson’s method (up to two decimal places) is__________.