Communication Systems

Exercise: Communication Systems

Each frequency in the modulating wave gives rise to four side bands.

True

False

Answer: B

Each frequency gives two side bands.

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In a communication system, noise is most likely to affect the signal

at the receiver

at the transmitter

at the information source

in the channel

Answer: D

Noise is mostly generated in channel.

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The tape recorders used in homes have

common head and common amplifier system for recording and playback

different heads and amplifiers for recording and playback

same head but different amplifiers for recording and playback

different heads but same amplifier for recording and playback

Answer: A

Common head and common amplifier is used.

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To prevent overloading in the last IF amplifier one should use

variable sensitivity

squelch

double conversion

variable selectivity

Answer: A

Variable sensitivity prevents overloading.

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As the magnitude of reverse bias is increased, the capacitance of varactor diode

increases

decreases

first increase, then decreases

first decreases then increases

Answer: B

When magnitude of reverse bias is increased, thickness of depletion layer increases.

Capacitance is inversely proportional to thickness.

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