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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Q. Which of the following is most likely to be found in an SSB transmitter?

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Q. Which one of the following frequency bands is allocated by ITU (International Telecomm. Union) for DBS - (Direct Broadcast service) also referred as DTH - (Direct to Home service)?

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Q. FM broadcast lies in which band?

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Q. Which colour picture tube uses slotted aperture mask?

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Q. If the circumference of a spherical target is between 1 to 10 wavelength in a radar system, the situation is called

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Q. The complete video signal consists of

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Q. Transit time is considered as significant at

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Q. In a colour TV receiver, AGC adjusts the gain of

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Q. In pulse transmitter the ratio of time on to time off is called

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