Fundamentals of Analog Communication

The main purpose of a communication system is to:

• Store information

• Transfer information from source to destination

• Encode information only

• Increase bandwidth

In a communication system, noise is usually added:

• At the transmitter

• At the receiver

• In the channel

• During modulation

Which block is responsible for translating a low-frequency message to a high-frequency signal?

• Transducer

• Modulator

• Amplifier

• Demodulator

In AM, the carrier amplitude varies according to:

• Carrier frequency

• Message signal

• Carrier phase

• Noise signal

In AM, overmodulation occurs when:

• m1m > 1m>1

• m=0m = 0m=0

The bandwidth of an AM signal is:

• Equal to carrier frequency

• Twice the highest modulating frequency

• Equal to modulating frequency

• Half the carrier frequency

In an AM system, if carrier power is 100 W and modulation index is 1, total transmitted power is:

• 100 W

• 125 W

• 150 W

• 200 W

In FM, the information is carried by:

• Amplitude variations

• Frequency variations

• Phase variations

• Carrier amplitude

In PM, the modulation index depends on:

• Modulating frequency

• Amplitude of the modulating signal

• Both frequency & amplitude of the modulating signal

• Carrier frequency only

The maximum frequency deviation in FM is:

• Directly proportional to carrier frequency

• Independent of modulating signal

• Proportional to amplitude of modulating signal

• Proportional to bandwidth only