COMMUNICATION SYSTEMS QUIZ

The frequency range of 300 kHz to 3000 kHz is known as

High frequency

Medium frequency

Very high frequency

Low frequency

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Under ordinary circumstances, impulse noise can be reduced in

AM only

FM only

None of these

Both AM and FM

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For AM receivers the standard IF frequency is

106 kHz

455 kHz

10.7 MHz

1.07 MHz

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The modulation index of an FM is changed from 0 to 1. How does the transmitted power change?

Gets halved

Gets increased by 50 percent

Remains unchanged

Gets doubled

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In case of frequency modulation, modulating voltage remains constant if the modulating frequency is lowered, then

Amplitude of distant sidebands decreases

Amplitude of distant sidebands first increases, then decreases

Amplitude of distant sidebands increases

Amplitude of distant sidebands remains constant

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

Impurities

Stepped index operation

Microbending

Attenuation in glass

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VSB modulation is preferred in TV because

It avoids phase distortion at low frequencies

None of these

It results in better reception

It reduces the bandwidth requirement to half

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For a plate-modulated class C amplifier the plate supply voltage is E. The maximum plate cathode voltage could be almost high as

6E

3E

2E

4E

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SSB can be generated by

Phase cancellation method

All of these

Good attenuation characteristics

Filter method

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Skip distance depends on time of day and angle of incidence.

False

True

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