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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 PYQ2014Digital CircuitsSequential CircuitsMCQ · 2 marks
The outputs of the two flip-flops Q1Q1, Q2Q2 in the figure shown are initialized to 0,00,0. The sequence generated at Q1Q1 upon application of clock signal is
Official PYQ2014Digital CircuitsComputer OrganizationMCQ · 2 marks
For the 80858085 microprocessor, the interfacing circuit to input 88-bit digital data (DI0−DI7)( DI_{0}-DI_{7}) from an external device is shown in the figure. The instruction for correct data transfer is
Official PYQ2014Networks, Signals and SystemsLTI SystemsNAT · 2 marks
Consider a discrete-time signal x[n]={nfor 0≤n≤100otherwise x[n]= \begin{cases} n & \text{for } 0\leq n\leq 10 \\ 0 & \text{otherwise }\end{cases} If y[n]y[n] is the convolution of x[n]x[n] with itself, the value of y[4]y[4] is _______ .
Official PYQ2014CommunicationsRandom ProcessesMCQ · 2 marks
The input-output relationship of a causal stable LTI system is given as y[n]=α y[n−1]+β x[n]y[n] = \alpha \: y[n-1] + \beta \: x[n]. If the impulse response h[n]h[n] of this system satisfies the condition ∑n=0∞h[n]=2\sum_{n=0}^{\infty}h[n]= 2, the relationship between α\alpha and β\beta is
Official PYQ2014Engineering MathematicsCalculusNAT · 2 marks
The value of the integral ∫−∞∞sinc2(5t) dt\int_{-\infty }^{\infty } \text{sinc}^{2}(5t) \: dt is _______.
Official PYQ2014Networks, Signals and SystemsLTI SystemsMCQ · 2 marks
An unforced linear time invariant (LTI) system is represented by [x1x2]=[−100−2][x1x2]\begin{bmatrix} x_1 \\ x_2 \end{bmatrix} = \begin{bmatrix} -1 & 0 \\ 0& -2 \end{bmatrix} \begin{bmatrix} x_1 \\ x_2 \end{bmatrix} If the initial conditions are x1(0)=1x_1(0)= 1 and x2(0)=−1x_2(0)= -1, the solution of the state equation is
Official PYQ2014Control SystemsNAT · 2 marks
The Bode asymptotic magnitude plot of a minimum phase system is shown in the figure. If the system is connected in a unity negative feedback configuration, the steady state error of the closed loop system, to a unit ramp input, is _________.
Official PYQ2014Networks, Signals and SystemsLTI SystemsMCQ · 2 marks
Consider the state space system expressed by the signal flow diagram shown in the figure. The corresponding system is
Official PYQ2014Engineering MathematicsProbability and StatisticsNAT · 2 marks
The input to a 11 – bit quantizer is a random variable XX with pdf fX(x)=2e−2xf_{X}( x )= 2e^{-2x} for x≥0x\geq 0 and fX(x)=0f_{X} (x )= 0 for x<0x< 0. For outputs to be of equal probability, the quantizer threshold should be ______.
Official PYQ2014CommunicationsDigital CommunicationsMCQ · 2 marks
Coherent orthogonal binary FSK modulation is used to transmit two equiprobable symbol waveforms s1(t)=αcos⁡2πf1ts_{1}( t )= \alpha \cos 2\pi f_1 t, and s2(t)=αcos⁡2πf2ts_2(t) = \alpha \cos 2 \pi f_2 t where α=4\alpha = 4 mV. Assume an AWGN channel with two-sided noise power spectral density No2=0.5×10−12\frac{N_o}{2}= 0.5 \times 10^{-12} W/Hz. Using an optimal receiver and the relation …
Official PYQ2014CommunicationsRandom ProcessesNAT · 2 marks
The power spectral density of a real stationary random process X(t)X(t) is given by SX(f)={1W,∣f∣≤W0,∣f∣>WS_X (f) = \begin{cases} \frac{1}{W}, & \mid f \mid \leq W \\ 0, & \mid f \mid > W \end{cases} The value of the expectation E[πX(t)X(t−14W)]E \left [ \pi X(t)X\left ( t-\frac{1}{4W} \right ) \right ] is __________.
Official PYQ2014Networks, Signals and SystemsContinuous-time SignalsNAT · 2 marks
In the figure, M(f)M(f) is the Fourier transform of the message signal m(t)m(t) where A=100A = 100 Hz and B=40B = 40 Hz. Given v(t)=cos⁡(2πfct)v(t)= \cos (2\pi f_{c}t) and w(t)=cos⁡(2π(fc+A)t)w(t)= \cos (2\pi (f_{c}+A)t), where fc>Af_{c}>A. The cutoff frequencies of both the filters are fcf_{c}. The bandwidth of the signal at the output of the modulater (in Hz) is ______.
Official PYQ2014ElectromagneticsPlane Waves and PropertiesMCQ · 2 marks
If the electric field of a plane wave is E→(z,t)=x^3cos⁡(ωt−kz+30∘)–y^4sin⁡(ωt–kz+45∘)(mV/m),\overrightarrow{E}(z,t)= \hat{x}3 \cos(\omega t-kz+30^{\circ}) – \hat{y} 4 \sin(\omega t – kz+45^{\circ}) (mV/m), the polarization state of the plane wave is
Official PYQ2014ElectromagneticsTransmission LinesNAT · 2 marks
In the transmission line shown, the impedance ZinZ_{\text{in}} (in ohms) between node A and the ground is _________.
Official PYQ2014ElectromagneticsTransmission LinesNAT · 2 marks
For a rectangular waveguide of internal dimension a×b (a>b)a\times b \: (a> b), the cut-off frequency for the TE11TE_{11} mode is the arithmetic mean of the cut-off frequencies for TE10TE_{10} mode and TE20TE_{20} mode. If a=5a= \sqrt{5} cm, the value of bb (in cm) is ______.
Official PYQ2014General AptitudeMCQ · 1 mark
“India is a country of rich heritage and cultural diversity.” Which one of the following facts best supports the claim made in the above sentence?
Official PYQ2014General AptitudeMCQ · 1 mark
The value of one U.S. dollar is 6565 Indian Rupees today, compared to 6060 last year. The Indian Rupee has ____________.
Official PYQ2014General AptitudeMCQ · 1 mark
'Advice' is ________________.
Official PYQ2014General AptitudeNAT · 1 mark
The next term in the series 81,54,36,24,…81, 54, 36, 24, \dots is ________
Official PYQ2014General AptitudeMCQ · 1 mark
In which of the following options will the expression P<MP < M be definitely true?