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GATE 2019: Communication Quiz 2 (App update required to attempt this test)

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Question 1

An AM modulator has output

The modulation efficiency is

Question 2

A sinusoidal signal of frequency 400Hz and amplitude 4 V phase modulates a carrier and produces 68 Rad deviation. The phase sensitivity is given by

Question 3

The modulating signal into an FM modulator is m(t) = 10 cos (16 πt) the output of the FM modulator is u(t) = 10 cos [400 πt + 2 πkf ] where kf = 10 Hz/V. If the output of the FM modulator is passed through an ideal BPF centered at fc = 2000 with a bandwidth of 65 Hz, determine the power of the frequency components at the output of the filter.

What is the approximate percentage of the transmitted power appears at the output of the BPF______ (%)

Question 4

An AM receiver operates with a single tone modulation and modulation index of m=0.3. The message signal is given by Description: Description: 08_Analog-Comm_BL-done_files\image042.png
The improvement in the output efficiency that results if modulation index is increased from 0.3 to 0.7 is

Question 5

An amplitude modulation signal has complex envelope as

Where
And the maximum amplitude of the carrier after modulation is given by 16 V, then unmodulated carrier amplitude is________ V.

Question 6

In a certain frequency modulation experiment conducted with fm =1KHz and increasing amplitude (starting from 0 V),it is found that carrier component of FM signal is reduced to zero for the first time when Am =2V
Given :Bessel function is zero for
X=2.44,5.52,8.65,11.8 and so on
The frequency sensitivity of the modulator is
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Jun 7ESE & GATE EC