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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SubjectTopicYearType

The phase velocity for the

\mathrm{TE}_{10}

– mode in an air-filled rectangular waveguide is (

c

is the velocity of plane waves in free space)

In an impedance Smith chart, a clockwise movement along a constant resistance circle gives rise to

\text{VSWR}

can have any value between

The line-of-sight communication requires the transmit and receive antennas to face each other. If the transmit antenna is vertically polarized, for best reception the receive antenna should be

For a bit-rate of

8 \; \mathrm{kbps}

, the best possible values of the transmitted frequencies in a coherent binary FSK system are

Consider a sampled signal

y(t)=5 \times 10^{\circ}

{ }^6 x(t) \sum_{(n-\infty}^{+\infty} \delta \left(t-n \mathrm{T}_x\right)

x(t)=10 \cos \left(8 \pi \times 10^3\right) t

T_s=100 \; \mu \mathrm{sec}

y(t)

is passed through an ideal lowpass filter with a cut-off frequency of 5

\mathrm{kHz}

, the output of the filter is

1 \; \mathrm{MHz}

sinusoidal carrier is amplitude modulated by a symmetrical square wave of period

100 \; \mu \mathrm{sec}

. Which of the following frequencies will NOT be present in the modulated signal?

A linear phase channel with phase delay

T_p

and group delay

T_g

f

denotes frequency)

The Fourier transform

\mathrm{F}\left\{e^{-t} u(t)\right\}

\frac{1}{1+j 2 \pi f}

\mathrm{F}\left\{\frac{1}{1+j 2 \pi t}\right\}

The transfer function

\mathrm{Y}(s) / \mathrm{U}(\mathrm{s})

of a system described by the state equations

x(t)=-2 x(t)+2 u(t)

y(t)=0.5 x(t)

The phase margin of a system with the open-loop transfer function

\mathrm{G}(s) \mathrm{H}(s)=\frac{(1-s)}{(1+s)(2+s)}

Which of the following points is NOT on the root locus of a system with the open-loop transfer function

\mathrm{G}(s) \mathrm{H}(s)=\frac{k}{s(s+1)(s+3)}

Consider a system with the transfer function

G(s)=\frac{s+6}{k s^2+s+6}

. Its damping ratio will be

0.5

when the value of

k

If the transistor in the figure is in saturation, then

The number of comparators required in a

3

-bit comparator type ADC is

If the input to the digital circuit the figure, consisting of a cascade of

20 \; \mathrm{XOR}

\mathrm{X}

, then the output

Y

4

2

's complement representation of a decimal number is

1000.

741

-type opamp has a gain-bandwidth product of

1 \; \mathrm{MHz}

. A non-inverting amplifier using this opamp and having a voltage gain of

20 \mathrm{~dB}

-3-\mathrm{dB}

In a negative feedback amplifier using voltage-series (i.e. voltage-sampling, series mixing) feedback. (

R_i

R_o

denote the input and output resistances respectively)

In given figure a silicon diode is carrying a constant current of

1 \mathrm{~mA}

. When the temperature of the diode is

20^{\circ} \mathrm{C}, \mathrm{V}_{\mathrm{D}}

700 \; \mathrm{mV}

. If the temperature rises to

40^{\circ} \mathrm{C}, \mathrm{V}_{\mathrm{D}}

becomes approximately equal to