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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 PYQ2006Analog CircuitsOp-amp CircuitsMCQ · 1 mark
For the circuit shown in the following figure, the capacitor CC is initially uncharged. At t=0t=0, the switch SS is closed. The voltage VCV_{C} across the capacitor at t=1t=1 millisecond is In the figure shown above, the OP AMP\text{OP AMP} is supplied with ±15 V\pm 15 \mathrm{~V} and the ground has been shown by the symbol ∇\nabla.
Official PYQ2006Digital CircuitsNumber RepresentationsMCQ · 1 mark
A new Binary Coded Pentary (BCP) number system is proposed in which every digit of a base-55 number is represented by tis corresponding 33-bit binary code. For example, the base-55 number 2424 will be represented by its BCP code 010100.010100. In this numbering system, the BCP code 100010011001100010011001 corresponds to the following number in base-55 …
Official PYQ2006Digital CircuitsCombinatorial CircuitsMCQ · 1 mark
An IO\frac{\mathrm{I}}{\mathrm{O}} peripheral device shown in Figure (b)(b) below is to be interfaced to an 80858085 microprocessor. To select the IO\frac{\mathrm{I}}{\mathrm{O}} device in the IO\frac{\mathrm{I}}{\mathrm{O}} address range D4H−D7H\mathrm{D} 4 \mathrm{H}-\mathrm{D} 7 \mathrm{H}, its chip-select (CS‾)(\overline{C S}) should be connected to …
Official PYQ2006Digital CircuitsSequential CircuitsMCQ · 1 mark
For the circuit shown in figure below, two 44-bit parallel-in serial-out shift registers loaded with the data shown are used to feed the data to a full adder. Initially, all the flip-flops are in clear state. After applying two clock pulses, the outputs of the fulladder should be
Official PYQ2006Digital CircuitsSequential CircuitsMCQ · 1 mark
Two D\text{D}-flip-flops, as shown below, are to be connected as a synchronous counter that goes through the following Q1Q0\mathrm{Q}_{1} \mathrm{Q}_{0} sequence 00⟶01⟶11⟶10⟶00⟶…00 \longrightarrow 01 \longrightarrow 11 \longrightarrow 10 \longrightarrow 00 \longrightarrow \dots The inputs D0D_{0} and D1D_{1} respectively should be connected as
Official PYQ2006Digital CircuitsComputer OrganizationMCQ · 1 mark
Following is the segment of a 80858085 assembly language program LXISP,EFFFH\text{LXISP,EFFFH} CALL 3000 H\text{CALL 3000 H} 3000H:LXIH,3CF4H3000 \mathrm{H}: \mathrm{LXIH}, 3 \mathrm{CF} 4 \mathrm{H} PUSH PSW\text{PUSH PSW} SPIH\text{SPIH} POP PSW\text{POP PSW} RET\text{RET} On completion of RET\text{RET} execution, the contents of SP\mathrm{SP} is
Official PYQ2006Digital CircuitsCombinatorial CircuitsMCQ · 1 mark
The point P\text{P} in the following figure is stuck-at-11. The output ff will be
Official PYQ2006Networks, Signals and SystemsContinuous-time SignalsMCQ · 1 mark
A signal m(t)m(t) with bandwidth 500 Hz500 \mathrm{~Hz} is first multiplied by a signal g(t)g(t) where g(t)=∑R=−∞∞(−1)kδ(t−0.5×10−4k)g(t)=\sum_{\mathrm{R}=-\infty}^{\infty}(-1)^{k} \delta\left(t-0.5 \times 10^{-4} k\right) The resulting signal is then passed through an ideal lowpass filter with bandwidth 1  kHz1 \; \mathrm{kHz}. The output of the lowpass filter would be
Official PYQ2006Networks, Signals and SystemsContinuous-time SignalsMCQ · 1 mark
The minimum sampling frequency (in samples/sec) required to reconstruct the following signal from its samples without distortion x(t)=5(sin⁡2π1000tπt)3+7(sin⁡2π1000tπt)2x(t)=5\left(\frac{\sin 2 \pi 1000 t}{\pi t}\right)^{3}+7\left(\frac{\sin 2 \pi 1000 t}{\pi t}\right)^{2} would be
Official PYQ2006Engineering MathematicsProbability and StatisticsMCQ · 1 mark
A uniformly distributed random variable XX with probability density function fγ(x)=110(tr(x+5)−u(x−5))f_{\gamma}(x)=\frac{1}{10}(t r(x+5)-u(x-5)) where u(.)u(.) is the unit step function is passed through a transformation given in the figure below. The probability density function of the transformed random variable YY would be
Official PYQ2006Networks, Signals and SystemsLTI SystemsMCQ · 1 mark
A system with input x[n]x[n] and output y[n]y[n] is given as y[n]=(sin⁡56πn)x(n)y[n]=\left(\sin \frac{5}{6} \pi n\right) x(n). The system is
Official PYQ2006Control SystemsMCQ · 1 mark
The unit-step response of a system starting from rest is given by C(t)=1−e−2t for t≥0\qquad C(t)=1-e^{-2 t} \text{ for } t \geq 0 The transfer function of the system is
Official PYQ2006Control SystemsMCQ · 1 mark
The Nyquist plot of G(jω)H(jω)\mathrm{G}(j \omega) \mathrm{H}(j \omega) for a closed loop control system, passes through (−1,j0)(-1, j 0) point in the GH\mathrm{GH} plane. The gain margin of the system in dB\mathrm{dB} is equal to
Official PYQ2006Control SystemsMCQ · 1 mark
The positive values of “K”\text{“K”} and “aa” so that the system shown in the figure below oscillates at a frequency of 2rad/sec2 \mathrm{rad} / \mathrm{sec} respectively are
Official PYQ2006Control SystemsMCQ · 1 mark
The unit impulse response of a system is h(t)=e−t,t≥0h(t)=e^{-t}, t \geq 0 For this system, the steady-state value of the output for unit step input is equal to
Official PYQ2006Control SystemsMCQ · 1 mark
The transfer function of a phase-lead compensator is given by Gc(s)=1+3Ts1+Ts where T>0G_{c}(s)=\frac{1+3 T s}{1+T s} \text{ where } T>0 The maximum phase-shift provided by such a compensator is
Official PYQ2006Control SystemsMCQ · 1 mark
A linear system is described by the following state equation X(t)=AX(t)+BU(t),A=[01−10]X(t)=\mathrm{AX}(t)+\mathrm{BU}(t), \mathrm{A}=\left[\begin{array}{cc} 0 & 1 \\ -1 & 0\end{array}\right] The state-transition matrix of the system is
Official PYQ2006Networks, Signals and SystemsContinuous-time SignalsMCQ · 1 mark
The minimum step-size required for a Delta-Modulator operating at 32 K32 \mathrm{~K} samples/ sec\mathrm{sec} to track the signal (here u(t)u(t) is the unit-step function) x(t)=125t(u(t)−u(t−1))+(250−125t)(u(t−1)−u(t−2))\begin{array}{l}x(t)=125 t(u(t)-u(t-1))+(250-125 t)(u(t-1) -u(t-2)) \end{array} so that slope-overload is avoided, would be
Official PYQ2006CommunicationsRandom ProcessesMCQ · 1 mark
A zero- mean white Gaussian noise is passed through an ideal lowpass filter of ban width 10  kHz10 \; \mathrm{kHz}. The output is the uniformly sampled with sampling period ts=0.03  msect_{s}=0.03 \; \mathrm{msec}. The samples so obtained would be
Official PYQ2006CommunicationsInformation TheoryMCQ · 1 mark
A source generates three symbols with probabilities 0.25,0.25,0.500.25,0.25,0.50 at a rate of 30003000 symbols per second. Assuming independent generation of symbols, the most efficient source encoder would have average bit rate as