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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 PYQ1999General AptitudeMCQ · 1 mark
Identify which of the following is NOT\text{NOT} a true of the graph shown in the given figure is
Official PYQ1999ElectromagneticsMaxwell's EquationsMCQ · 1 mark
Identify which one of the following will NOT\text{NOT} satisfy the wave equation.
Official PYQ1999ElectromagneticsTransmission LinesMCQ · 1 mark
Indicate which one of the following will NOT\text{NOT} exist in a rectangular resonant cavity.
Official PYQ1999ElectromagneticsTransmission LinesMCQ · 1 mark
Assuming perfect conductors of a transmission line, pure TEM\text{TEM} propagation is NOT\text{NOT} possible in
Official PYQ1999ElectromagneticsMaxwell's EquationsMCQ · 1 mark
An electric field on a plane is described by its potential V=20(r−1+r−2)\mathrm{V}=20\left(r^{-1}+r^{-2}\right) where rr is the distance from the source. The field is due to
Official PYQ1999Networks, Signals and SystemsContinuous-time SignalsMCQ · 1 mark
A modulated signal is given by s(t)=e−atcos⁡[(ωc+Δω)t]u(t),s(t)=e^{-a t} \cos \left[\left(\omega_{c}+\Delta \omega\right) t\right] u(t), where a,ωca, \omega_{c} and Δω\Delta \omega are positive constants, and ωc≫Δω\omega_{c} \gg \Delta \omega. The complex envelope of s(t)s(t) is given by
Official PYQ1999CommunicationsAnalog CommunicationsMCQ · 1 mark
A modulated signal is given by, s(t)=m1(t)cos⁡(2πfct)+m2(t)sin⁡(2πfct)s(t)=m_{1}(t) \cos \left(2 \pi f_{c} t\right)+m_{2}(t) \sin \left(2 \pi f_{c} t\right) where the baseband signal m1(t)m_{1}(t) and m2(t)m_{2}(t) have bandwidths of 10  kHz10 \; \mathrm{kHz} and 15  kHz15 \; \mathrm{kHz}, respectively. The bandwidth of the modulated signal, in kHz\mathrm{kHz}, is
Official PYQ1999CommunicationsAnalog CommunicationsMCQ · 1 mark
The input to a channel is a bandpass signal. It is obtained by linearly modulating a sinusoidal carrier with a single-tone signal. The output of the channel due to this input is given by y(t)=(1/100)cos⁡(100t−10−6)cos⁡(106t−1.56)y(t)=(1 / 100) \cos \left(100 t-10^{-6}\right) \cos \left(10^{6} t-1.56\right) The group delay (tg)\left(t_{g}\right) and the phase delay (tp)\left(t_{p}\right) in …
Official PYQ1999Networks, Signals and SystemsContinuous-time SignalsMCQ · 1 mark
A signal x(t)x(t) has a Fourier transform X(ω)X(\omega). If x(t)x(t) is a real and odd function of tt, then X(ω)X(\omega) is
Official PYQ1999Control SystemsMCQ · 1 mark
The phase margin (in degrees) of a system having the loop transfer function G(s)H(s)=23s(s+1) is \mathrm{G}(s) \mathrm{H}(s)=\frac{2 \sqrt{3}}{s(s+1)} \text{ is }
Official PYQ1999Control SystemsMCQ · 1 mark
The system moded described by the state equations is X=[012−3]x+[01]uY=[11]x\begin{array}{l} \mathrm{X}=\left[\begin{array}{cc} 0 & 1 \\ 2 & -3 \end{array}\right] x+\left[\begin{array}{l} 0 \\ 1 \end{array}\right] u \\ \mathrm{Y}=\left[\begin{array}{ll} 1 & 1 \end{array}\right] x \end{array}
Official PYQ1999Control SystemsMCQ · 1 mark
The gain margin (in dBd \mathrm{B} ) of a system a having the loop transfer function G(s)H(s)=2s(s+1) is \mathrm{G}(s) \mathrm{H}(s)=\frac{\sqrt{2}}{s(s+1)} \text{ is }
Official PYQ1999Control SystemsMCQ · 1 mark
For a second-order system with the closed-loop transfer function T(s)=9s2+4s+9T(s)=\frac{9}{s^{2}+4 s+9} the settling time for 22 - percent band, in seconds, is
Official PYQ1999Digital CircuitsData ConvertersMCQ · 1 mark
The resolution of a 44 - bit counting ADC\text{ADC} is 0.50.5 volts. For an analog input of 6.66.6 volts, the digital output of the ADC\text{ADC} will be
Official PYQ1999Digital CircuitsCombinatorial CircuitsMCQ · 1 mark
Commercially available ECL\text{ECL} gears use two ground lines and one negative supply in order to
Official PYQ1999Analog CircuitsBJT and MOSFET AmplifiersMCQ · 1 mark
A Darlington emitter - follower circuit is sometimes used in the output stage of a TTL\text{TTL} gate in order to
Official PYQ1999Digital CircuitsCombinatorial CircuitsMCQ · 1 mark
The logical expresion y=A+A‾By=\mathrm{A}+\overline{\mathrm{A}} \mathrm{B} is equivalent to
Official PYQ1999Analog CircuitsBJT and MOSFET AmplifiersMCQ · 1 mark
Crossover distortion behaviour is characteristic of
Official PYQ1999Analog CircuitsBJT and MOSFET AmplifiersMCQ · 1 mark
In the cascade amplifier shown in the given figure, if the common - emitter stage (Q1)\left(Q_{1}\right) has a transconductance gm1\mathrm{gm}_{1}, and the common base stage (Q2)\left(Q_{2}\right) has a transconductance gm2′\mathrm{gm}_{2^{\prime}}, then the overall transconductance g(=i0/v1)g\left(=i_{0} / v_{1}\right) of the cascade amplifier is
Official PYQ1999Analog CircuitsOp-amp CircuitsMCQ · 1 mark
Negative feedback in an amplifier