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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 PYQ1999CommunicationsDigital CommunicationsMCQ · 1 mark
The input to a matched filter is given by s(t)={100sin⁡(2π×106t)0<1<10−4secotherwises(t) = \left\{\begin{matrix} 10\\ 0 \end{matrix}\right. \begin{array}{ll} \sin \left(2 \pi \times 10^{6} t\right) & 0<1<10^{-4} \mathrm{sec} \\ & \text{otherwise} \end{array} The peak amplitude of the filter output is
Official PYQ1999CommunicationsDigital CommunicationsMCQ · 1 mark
The peak-to-peak input to an 88-bit PCM\text{PCM} coder is 22 volts. The signal power-to-quantization noise power ratio (in dBd\text{B}) for an input of 0.5cos⁡(ωmt)0.5 \cos \left(\omega_{m} t\right) is
Official PYQ1999Networks, Signals and SystemsContinuous-time SignalsMCQ · 1 mark
The Nyquist sampling frequency (in Hz\mathrm{Hz} ) of a signal given by 6×104sin⁡c2(400t)∗106sin⁡c3(100t)6 \times 10^{4} \sin c^{2}(400 t)^{*} 10^{6} \sin c^{3}(100 t) is
Official PYQ1999Networks, Signals and SystemsDiscrete-time SignalsMCQ · 1 mark
The zz-transform of a signal is given by C(z)=1z−1(1−z−4)4(1−z−1)2C(z)=\frac{1 z^{-1}\left(1-z^{-4}\right)}{4\left(1-z^{-1}\right)^{2}} Its final value is
Official PYQ1999Control SystemsMCQ · 1 mark
For the system described by the state equation x=[0100010.512]x+[001]ux=\left[\begin{array}{ccc} 0 & 1 & 0 \\ 0 & 0 & 1 \\ 0.5 & 1 & 2 \end{array}\right] x+\left[\begin{array}{l} 0 \\ 0 \\ 1 \end{array}\right] u If the control signal uu is given by u=[−0.5−3−5]u=[-0.5-3-5] x+vx+v, then the eigenvalues of the closed-loop system will be
Official PYQ1999Control SystemsMCQ · 1 mark
Consider the points s1=−3+j4s_{1}=-3+j 4 and s2=−3−j2s_{2}=-3-j 2 in the ss-plane. Then, for a system with the open-loop Transfer function G(s)H(s)=K(s+1)4G(s) H(s)=\frac{K}{(s+1)^{4}}
Official PYQ1999Control SystemsMCQ · 1 mark
If the closed-loop transfer function T(s)T(s) of a unity negative feedback system is given by T(s)=an−1 s+an sn+n1sn−1+…+an−1s+an\mathrm{T}(\mathrm{s})=\frac{a_{n -1} \mathrm{~s}+a_{n}}{\mathrm{~s}^{n}+n_{1} s^{n-1}+\ldots+a_{n-1} s+a_{n}} then the steady state error for a unit ramp input is
Official PYQ1999Digital CircuitsComputer OrganizationMCQ · 1 mark
If CS=A15   A14  A13\text{CS}=\text{A}_{15} \; \text{ A}_{14} \; \text{A}_{13} is used as the chip select logic of a 4  K RAM4 \; \text{K RAM} in an 80858085 system, then its memory range will be
Official PYQ1999Digital CircuitsSequential CircuitsMCQ · 1 mark
The ripple counter shown in the given figure is works as a
Official PYQ1999Digital CircuitsCombinatorial CircuitsMCQ · 1 mark
For a binary half-subtractor having two inputs A\text{A} and B\text{B}, the correct set of logical expressions for the outputs D\text{D} ( = A\text{A} minus B\text{B} ) and X(=\text{X}(= borrow) are
Official PYQ1999Digital CircuitsCombinatorial CircuitsMCQ · 1 mark
The minimized form of the logical expression (AˉBˉCˉ+AˉBCˉ+AˉBC+ABCˉ)(\bar{A} \bar{B} \bar{C}+\bar{A} B \bar{C}+\bar{A} B C+A B \bar{C}) is
Official PYQ1999Analog CircuitsBJT and MOSFET AmplifiersMCQ · 1 mark
An amplifier is assumed to have a single-pole high-frequency transfer function. The rise time of its output response to a step function input is 35  nsec35\;\text{nsec}. The upper −3  dB-3 \; d B frequency (in MHz\text{MHz}) for the amplifier to a sinusoidal input is approximately at
Official PYQ1999Networks, Signals and SystemsCircuit AnalysisMCQ · 1 mark
A dc\text{dc} power supply has a no-load voltage if 30 V30 \mathrm{~V}, and a full-load voltage of 25 V25 \mathrm{~V} at a full - load current of 1 A1 \mathrm{~A}. Its output resistance and load regulation, respectively, are
Official PYQ1999Analog CircuitsOp-amp CircuitsMCQ · 1 mark
An amplifier has an open-loop gain of 100100, an input impedance of 1  kΩ1 \; \mathrm{k \Omega}, and an output impedance of 100  Ω100 \; \Omega. A feedback network with a feedback factor of 0.990.99 is connected to the amplifier in a voltage series feedback mode. The new input and output impedances, respectively, are
Official PYQ1999Analog CircuitsBJT and MOSFET AmplifiersMCQ · 1 mark
An npn\text{npn} transistor (with C=0.3  pF\mathrm{C}=0.3 \; \mathrm{pF} ) has a unity gain cutoff frequency fTf_{\mathrm{T}} of 400  MHz400 \; \mathrm{MHz} at a dc\text{dc} bias current Ic=1 mAI_{c}=1 \mathrm{~mA}. The value of its CμC_{\mu} (in  pF\mathrm{~pF} ) is approximately (VT=26  mV)\left(\mathrm{V}_{\mathrm{T}}=26 \; \mathrm{mV}\right)
Official PYQ1999Analog CircuitsBJT and MOSFET AmplifiersMCQ · 1 mark
An nn-channel JEFT\text{JEFT} has IDSS=2 mA\mathrm{I}_{\mathrm{DSS}}=2 \mathrm{~mA} and Vp=−4 V\mathrm{V}_{p}=-4 \mathrm{~V}. Its transconductance gm\mathrm{gm} (in milliohm) for an applied gate-to-source voltage VGS\mathrm{V}_{\mathrm{GS}} of −2 V-2 \mathrm{~V} is
Official PYQ1999Networks, Signals and SystemsCircuit AnalysisMCQ · 1 mark
A Delta-connected network with its Wye-equivalent is shown in the given figure is. The resistances R1,R2R_{1}, R_{2} and R3R_{3} (in ohms) are respectively
Official PYQ1999Networks, Signals and SystemsCircuit AnalysisMCQ · 1 mark
The Thevenin equivalent voltage VTH\mathrm{V}_{\mathrm{TH}} appearing between the terminals AA and BB of the network shown in the given figure is given by
Official PYQ1999Networks, Signals and SystemsContinuous-time SignalsMCQ · 1 mark
The Fourier series representation of an impules train denoted by s(t)=∑n=−∞nd(t−n T0) is given by s(t)=\sum_{n=-\infty}^{n} d\left(t-n \mathrm{~T}_{0}\right) \text{ is given by }
Official PYQ1998Electronic DevicesMCQ · 1 mark
The units of qkT\frac{q}{k T} are