Q. Entropies associated with an extremely unlikely message and that with an extremely likely message are respectively

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Q. For TV broadcast, picture signal is modulated in

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Q. Assertion (A): Stubs, directional couplers and baluns are very commonly used in communication systems

Reason (R): Characteristic impedance of a line is an important parameter.

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Q. Audio frequency range lies between

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Q. Assertion (A): SSB and ISB receivers have good S/N ratio

Reason (R): SSB and ISB receivers have good suppression of adjacent channels.

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Q. De-emphasis circuit is used

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Q. Which is most important subsystem for recovering and reconstructing signal in a TDM system?

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Q. Which one of the following is an indirect way of generating FM?

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Q. Companding is used in PCM to

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Q. Assertion (A): In AM the amplitude of carrier is made proportional to the instantaneous amplitude of modulating wave

Reason (R): In AM, frequency of side band = frequency carrier ± frequency of modulating wave.

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Q. Pressing a key on telephone set generates two frequencies. The basis for selection of these frequencies is

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Q. Which of the following oscillator is not in FM?

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Q. The number of spectral component of impulse wave is

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Q. Assertion (A): If a carrier is modulated by three sine waves and m₁, m₂, m₃ are the modulation indices, the total modulation index mt is
mt = (m₁² + m₂² + m₃²)^0.5

Reason (R): An AM, higher the level of modulation, lower is the audio power required to produce modulation.

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Q. If M (jω) = £[m(t)] where £ denotes Fourier transform, then £[m(t) cos ωct] =

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Q. When a wave reaches the open circuited end of a line

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Q. Some features of RF stage in good radio receivers is

1. It increases sensitivity by providing amplification to RF signal
2. It eliminates image frequency interference
3. It increases selectivity
4. It reduces noise level

Which of the above are true?

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Q. During amplitude modulation, the phase angle of the modulating voltage changes by

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Q. The image frequency of a superheterodyne receiver is

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Q. Image frequency rejection mainly depends upon

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