Communication System

1.

Multiple Choice

45 sec

1 pt

Amplitude modulation is

Change in amplitude of the carrier according to modulating signal

Change in frequency of the carrier according to modulating signal

Change in amplitude of the modulating signal according to carrier signal

Change in amplitude of the carrier according to modulating signal frequency

2.

Multiple Choice

45 sec

1 pt

The graph shows the frequency spectrum of an AM radio wave carrying an audio signal of a single frequency. Determine the frequency of the audio signal.

1kHz

3 kHz

5 kHz

7 kHz

3.

Multiple Choice

45 sec

1 pt

An analogue signal is sampled at a frequency of 5.0 kHz. Each sample is converted into a four-bit number and transmitted as a digital signal. Show in which number equal to code 0110.

2

4

6

8

4.

Multiple Choice

45 sec

1 pt

The Y-input terminals of a cathode-ray oscilloscope (c.r.o.) are connected to a supply of amplitude 5.0V and frequency 50Hz. The time-base is set at 10ms per division and the Y- gain at 5.0V per division.

Which trace is obtained?

5.

Multiple Choice

45 sec

1 pt

Determine the maximum frequency of the transmitted audio signal

18 kHz

9 kHz

918 kHz

909 kHz

6.

Multiple Choice

45 sec

1 pt

Energy loss in wire because of ...

electrical heating

absorption

scattering

7.

Multiple Choice

45 sec

1 pt

To send a message from one person, thing, or place to another is an example of

decoding.

receiving.

transmitting.

storing.

8.

Multiple Choice

45 sec

1 pt

The person who originates the message is the ...

Receiver

Decoder

Source

Encoder

9.

Multiple Choice

45 sec

1 pt

VHF is a abbreviation for what

vast help frequencies

very high frequencies

very hot food

very helpful frequencies

10.

Multiple Choice

45 sec

1 pt

What is the point of a repeater

To say the message for a seconf time

turn high power signals into low power signals

top turn lower power signals into higher power signals

just to add a extra step in transmitting

11.

Multiple Choice

45 sec

1 pt

A complete communication system must include:

a transmitter and receiver

a transmitter, a receiver, and a channel

a transmitter, a receiver, and a spectrum analyzer

a multiplexer, a demultiplexer, and a channel

12.

Multiple Choice

45 sec

1 pt

The output transducer of the communication system converts the radio signal into

Sound

Mechanical energy

Kinetic energy

None of the above

13.

Multiple Choice

45 sec

1 pt

The signal is affected by noise in communication system

At the transmitter

At the modulator

In the channel

At the receiver

14.

Multiple Choice

45 sec

1 pt

The variation of frequency of carrier wave with respect to the amplitude of the modulating signal

Amplitude modulation

Frequency modulation

Phase modulation

Pulse width modulation

15.

Multiple Choice

45 sec

1 pt

Which of the following is NOT a type of transmission channel?

Coaxial cable

Twisted pair

Modem

Microwave

16.

Multiple Choice

45 sec

1 pt

Which of the following statements best describes data transmission?

The process of removing data from one specific location

Communication on the Internet

The process of transferring data from one point to another

The process of securing data in a network

17.

Multiple Choice

45 sec

1 pt

The speed of transmission is described with what term?

Broadband

Bandwidth

Connection Speed

Ping

18.

Multiple Choice

45 sec

1 pt

A hearing aid is a small device that contains an amplifier, a battery, a microphone, and a speaker. Which part of a hearing aid functions to detect sounds in the user’s environment?

the battery

the amplifier

the speaker

the microphone

19.

Multiple Choice

45 sec

1 pt

The picture shows a television satellite dish. The satellite dish is an example of which of the following components of a television communications system?

decoder

encoder

receiver

transmitter

20.

Multiple Choice

45 sec

1 pt

Which of the following identifies the primary function of a radio station tower in a communication system?

transmitter

encoder

decoder

receiver

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