COMMUNICATION SYSTEMS QUIZ

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

Harmonic devices

Class C amplifiers

Linear devices

Non-linear devices

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The main function of a balanced modulator is to

Limit noise picked by a receiver

Produce 100% modulation

Suppress carrier signal in order to create a single-sideband or double sideband

Produce balanced modulation of a carrier wave

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A modem is classified as low speed if data rate handled is

Upto 100 bps

Upto 250 bps

Upto 600 bps

Upto 400 bps

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A buffer amplifier is

None of these

A cathode follower stage

A double-tuned amplifier

A high gain D.C. amplifier

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Commercial Frequency deviation of FM is

80 kHz

65 kHz

75 kHz

70 kHz

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Fourier analysis indicate that a square wave can be represented as

Fundamental and subharmonic sine waves

A fundamental sine wave and odd harmonics

A fundamental sine wave and even harmonics

A fundamental sine wave and harmonics

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If sampling is done at the rate of 10 kHz. The bandwidth required is

70 kHz

1280 kHz

10 kHz

35 kHz

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One of the advantages of base modulation over collector modulation of a transistor class C amplifier is

Better linearity

Improved efficiency

The lower modulating power requirement

High power output per transistor

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Which of the following does not cause losses in optical fibre cables?

Stepped index operation

Impurities

Microbending

Attenuation in glass

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If output power of a radio receiver is doubled, its volume is increased by __________ dB.

2

3

1

-3

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