Q. Assertion (A): In AM carrier component remains constant in amplitude and frequency.

Reason (R): In AM the two side bands are images of each other.

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Q. In tape recorders the hissing noise is due to irregularities in magnetic coating on tape.

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Q. The main advantage of TDM over FDM is

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Q. In FM reception, amplitude disturbances due to static change

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Q. In a colour TV receiver, PAL Dematrix consists of

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Q. For a resistance of about 15 kΩ operating in a frequency range of a few MHz, the noise voltage is in the range of

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Q. In a 50 cm TV tube, a path difference of 2 km between direct wave and interfering wave would mean a displacement between main image and ghost image equal to

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Q. In a colour TV receiver, the sound intercarrier IF is generated in

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Q. Consider the following types of distortions in diode detectors

1. Distortion is caused due to the reason that dc and ac load impedances are unequal
2. Distortion is caused because ac load impedance has a reactive component at high audio frequencies
3. Audio frequency diode current is less than dc current

Which of the above are true?

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Q. Satellites used for international communication are called

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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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