GATE EC Analog Communications questions

Practise Analog Communications questions for GATE EC. Explore official PYQs and original topic-wise quizzes, check answers and view available solutions. Free, no sign-in.

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SubjectTopicYearType

The image channel selectivity of superheterodyne receiver depends upon

A parabolic dish antenna has a conical beam

2^{\circ}

wide, the directivity of the antenna is approximately

An amplifier A has

6 \; d \mathrm{B}

gain and

50 \; \Omega

input and output impedances. The noise figure of this amplifier as shown in the figure is

(a)

3 \; d \mathrm{B}

. A cascade of two such amplifiers as in the figure is will have a noise figure of

The image channel rejection in a superheterodyne receiver comes from

1 \mathrm{~km}

long microwave link uses two antennas each having

30 \mathrm{~dB}

gain. If the power transmitted by one antenna is

1 \mathrm{~W}

3 \; \mathrm{GHz}

, the power received by the other antenna is approximately

The critical frequency of an ionospheric layer is

10 \; \mathrm{MHz}

. What is the maximum launching angle from the horizon for which

20 \; \mathrm{MHz}

wave will be reflected by the layer?

\text{FM}

signal with a modulation index

9

is applied to a frequency tripler. The modulation index in the output signal will be

\text{PLL}

can be used to demodulate

The image (second) channel selectivity of a super beterodync communication receiver is determined by

For a short wave radio link between two stations via the ionosphere, the ratio of the maximum usable frequency to the critical frequency

Medium wave radio signals may be received at far off distances at night because

v(t)=5[\cos (106 \; \pi t)-\sin (103 \; \pi t) \times \sin (106 \; \pi t)

represents

Which of the following demodulator(s) can be used for demodulating the signal

x(t)=5(1+2 \cos 2000 \pi t) \cos 2000 \pi t .

The maximum power efficiency of an

\text{AM}

modulator is