COMMUNICATION SYSTEMS QUIZ

A buffer amplifier is

A cathode follower stage

None of these

A high gain D.C. amplifier

A double-tuned amplifier

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Which of the following is used to generate PDM?

JK flip-flop

Monostable multi-vibrator

Schmitt trigger

Free running multi-vibrator

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For attenuation of high frequencies we should use

Series capacitance

Shunt capacitance

Inductance

Resistance

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When the length of antenna is a whole wavelength

The radiation at right angles is zero

The radiation is zero in all directions

The radiation at right angles is maximum

The radiation is maximum in all directions

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For a low level AM system, the amplifiers modulated stage must be

Class C amplifiers

Linear devices

Non-linear devices

Harmonic devices

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If in a broadcasting studio, a 1000 kHz carrier is modulated by an audio signal of frequency range 100-5000 kHz, the width of channel is __________ kHz.

4.9

995

5

10

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DVD uses

None of these

Laser beam for both recording and playback

Video head for recording and laser beam for playback

Laser beam for recording and video head for playback

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In case of low level amplitude modulation system, the amplifiers following the modulated stage must be

Non-linear devices

Linear devices

Harmonic devices

Class C amplifiers

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The disadvantage of FM over AM is that

Noise is very high for high frequency

High output power is needed

High modulating power is needed

Large bandwidth is required

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In Modulation, “carrier” is

Resultant wave

Speech voltage to be transmitted

Voltage for which frequency, phase or amplitude is varied

Voltage with constant frequency, phase or amplitude

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