Q. In a phase discriminator fc, is the IF to which primary circuit is tuned. Consider the following statements:
The primary and secondary voltages are

1. exactly 90° out of phase when input frequency is fc
2. more than 90° out of phase when input frequency is higher than fc
3. less than 90° out of phase when input frequency is lower than fc

Which of the above statements is correct?

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Q. Electronic tubes used for transmitter differ from their counterparts in the receivers in respect that

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Q. A plot of modulation index vs carrier amplitude yields a

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Q. On modulating a carrier of frequency fc by an audio signal fs, the following components has resulted:

fc, fc + fs and fc - fs

What is this type of modulation likely to be?

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Q. Strength of space wave is not dependent on distance.

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Q. Which of the following is not necessarily the advantage of SSB over double sideband, full carrier AM?

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Q. A signal m(t) = 5 cos 2π 100 t frequency modulates a carrier. The resulting FM signal is

10 cos {(2π10⁵ t) + 15 sin (2π 100 t)}

The approximate bandwidth of the FM would be

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Q. Some possible functions of AGC in a TV receiver are

1. To increase gain for weak signals
2. To decrease gain for strong signals
3. To change the contrast when we switch from one channel to other
4. To reduce flutter

Which of the above are correct?

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Q. The satellites used for intercontinental communication are called

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Q. Armoured submarine cable is used

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Q. The frequency deviation of a FM signal produced from PM is

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Q. Good frequency stability can be available

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Q. Assertion (A): The unit of telephone traffic measurement is erlang.

Reason (R): International circuits for communication are fitted with echo suppressors.

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Q. The primary colours are

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Q. The most commonly used system of modulating for telegraphy is

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Q. Which of the following antennas is not wide band?

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Q. In phase shift keying the input signal is

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Q. A circuit which cannot demodulate SSB is

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Q. In TV system in India IF video and IF audio frequencies are

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Q. While AM has __________ frequencies, FM has __________ number of sidebands.

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