COMMUNICATION SYSTEMS QUIZ

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 increases

Amplitude of distant sidebands remains constant

Amplitude of distant sidebands first increases, then decreases

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Under ordinary circumstances, impulse noise can be reduced in

FM only

Both AM and FM

AM only

None of these

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

Non-linear devices

Linear devices

Harmonic devices

Class C amplifiers

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For telegraphy the most commonly used modulation system is

FSK

PCM

Single tone modulation

Two tone modulation

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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 harmonics

A fundamental sine wave and odd harmonics

A fundamental sine wave and even harmonics

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

Low frequency

High frequency

Very high frequency

Medium frequency

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PAM stands for

Pulse Analogue Modulation

Phase Amplitude Modulation

Pulse Amplitude Modulation

Phase Analogue Modulation

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The characteristic impedance of a twin wire feeder used for TV signals is about

300 ohm

500 ohm

100 ohm

1000 ohm

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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 AM receivers the standard IF frequency is

106 kHz

455 kHz

1.07 MHz

10.7 MHz

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