principle electronics

Question 1

what century did electronic communication begin?

Answer 1

19th century

Question 2

Five types of media; three most common

Answer 2

Wire cable, free space (radio and light), fiber-optic cable, water, the earth. The first three are the most widely used.

Question 3

Four main elements of a communication system

Answer 3

Transmitter → Medium → Receiver → Noise
(Diagram: Information Source → Transmitter → Medium/Channel → Receiver → Destination)

Question 4

Device used to convert info to a medium-compatible signal

Answer 4

transmitter/modulator

Question 5

Device that recovers the original information

Answer 5

receiver/demodulator

Question 6

What is a transceiver?

Answer 6

A device that both transmits and receives signals.

Question 7

Two ways a medium affects a signal:

Answer 7

Attenuation, distortion

Question 7

Another name for communication medium

Answer 7

Communications channel

Question 8

Three common sources of interference

Answer 8

Lightning, outer space (sun, stars), manufactured devices (motors, car ignitions, fluorescent lights, etc.

Question 8

Name for unwanted interference in a signal

Answer 8

Noise

Question 9

Name of original info/intelligence signal

Answer 9

baseband signals

Question 10

Two forms of intelligence signals

Answer 10

analog and digital

Question 10

Name for two-way simultaneous communication and examples

Answer 10

Full-duplex. Telephones: standard, cordless, cellular

Question 11

Name for one-way communication and examples

Answer 11

Simplex. Broadcasting, paging, telemetry

Question 12

Continuously varying voice/video signals are

Answer 12

analog

Question 13

Name for two-way but turn-based communication and examples

Answer 13

Half-duplex. Two-way radio, fax machine, computer modem

Question 13

How are analog voice/video sent digitally

Answer 13

The analog signals are converted into binary signals first

Question 14

On/off intelligence signals are called

Answer 14

digital or binary

Question 15

Terms used for original voice/video/data signals

Answer 15

Information or intelligence signals or baseband signals

Question 16

Technique to make signals compatible with the medium

Answer 16

modulation

Question 17

Process of recovering original signal

Answer 17

Demodulation or detection

Question 18

What is a broadband signal

Answer 18

a carrier modulated by one or more basebands

Question 19

Process of sending multiple baseband signals over one medium

Answer 19

multiplexing

Question 20

Human hearing range

Answer 20

20 Hz to 20 kHz

Question 20

Technique to extract multiple intelligence signals

Answer 20

demultiplexing

Question 20

Wavelength calculations: Use the formula λ = c / f (c = 3 × 10⁸ m/s) 1.5 kHz 18 MHz 22 GHz

Answer 20

124.2 miles, 54.67 ft, 1.36 cm

Question 21

Why aren’t audio signals transmitted directly?

Answer 21

Antennas would be too long to be practical, signals would not travel far, all signals would interfere with one another. / low frequency and not efficiently radiated

Question 21

Do radio transmissions occur in VLF and LF ranges?

Answer 21

Yes, mostly for military and navigation

Question 21

Name for signals traveling long distances through free space

Answer 21

radio or wireless

Question 22

What is a radio wave made of?

Answer 22

Electric or magnetic fields

Question 23

Approximate voice frequency range

Answer 23

300–3000 Hz / 300 Hz to 3.4 kHz

Question 24

Frequency range of AM radio broadcast stations

Answer 24

535–1705 kHz.

Question 25

TV channels 2–13 and FM broadcasting appear in

Answer 25

VHF (30 to 300 MHz)

Question 25

Radio signals in high-frequency range

Answer 25

Short waves (HF band: 3–30 MHz)

Question 26

Five uses of the UHF band

Answer 26

Two-way radio, TV, cellular telephone, radar, satellites

Question 27

Frequencies above 1 GHz are called

Answer 27

Microwave

Question 28

Frequencies above EHF range

Answer 28

Millimeter wave / Infrared, visible light, and optical

Question 29

What is a micrometer

Answer 29

A micron is one-millionth of a meter or micrometer (µm) or 10–6 m. It is used to express light wavelength.

Question 30

Two ways to transmit visual data by telephone

Answer 30

Facsimile and television

Question 30

Three segments of optical frequency spectrum

Answer 30

Infrared, visible, ultraviolet

Question 30

Two media used for light communication

Answer 30

Free space and fiber-optic cable

Question 31

Infrared spectrum range

Answer 31

0.7 to 100 µm / 750 nm to 100 µm

Question 32

common source of infrared signals

Answer 32

Heated objects or LEDs and lasers

Question 33

Angstrom and its use

Answer 33

An angstrom is 10–10 m and is used to state light wavelength, like x rays

Question 34

Wavelength range of visible light

Answer 34

0.4 to 0.8 µm / 400–700 nm

Question 35

Signaling individuals remotely by radio

Answer 35

paging

Question 36

Four ways radio is used in phones

Answer 36

Cordless telephones, cellular telephones, microwave relay, satellites

Question 36

Term for measuring from a distance

Answer 36

Telemetry

Question 37

Principle used in radar

Answer 37

The reflection of radio waves from a distant object

Question 38

Underwater radar and examples

Answer 38

Sonar. - Passive sonar listens to underwater sounds. - Active radar sends out an ultrasonic signal and listens for its reflection or echo to determine range and bearing

Question 39

Popular radio hobby

Answer 39

Amateur or ham radio.

Question 39

Device for digital data over phone lines

Answer 39

modem

Question 40

Synonym for radio

Answer 40

wireless

Question 40

Network of interlinked computers

Answer 40

lan

Question 41

Three technical roles in communication

Answer 41

Engineer, technologist, technician

Question 42

Main job of an engineer

Answer 42

Design and analysis of circuits, equipment, and systems

Question 43

What is the primary degree for an engineer?

Answer 43

Bachelor’s degree

Question 44

type of technical degree in engineering other than engineer or technician.

Answer 44

Bachelor’s degree in technology.

Question 44

primary degree for a technician?

Answer 44

Associate’s degree

Question 45

62. List three other types of jobs in the field of electronic communication that do not involve engineering or technician’s work.

Answer 45

Sales, technical writing, training.

Question 45

60. Can the holder of an associate of technology degree transfer the credits to an engineering degree program?

Answer 45

no

Question 45

64. Why are standards important

Answer 45

to ensure compatibility and interoperability of equipment

Question 45

63. What are the four main segments of the communication industry? Explain briefly the function of each.

Answer 45

Manufacturers create products, distributors transfer products to resellers who market the products, service organizations install, repair, and maintain the products, and end users apply the products.

Question 45

61. What types of work does a technician ordinarily do?

Answer 45

Install, operate, maintain, troubleshoot, repair, and service equipment.

Question 46

65. What types of characteristics do communication standards define?

Answer 46

define modulation and/or multiplexing methods, frequencies of operation, protocols, and interface methods, including mechanical connections

Question 47

66. Calculate the frequency of signals with wavelengths of 40 m, 5 m, and 8 cm.

Answer 47

7.5 MHz, 60 MHz, 3750 MHz, or 3.75 GHz.

Question 48

67. In what frequency range does the common ac power line frequency fall

Answer 48

elf 30-300 hz vlf 3-30khz

Question 49

68. What is the primary use of the SHF and EHF ranges

Answer 49

Radar and satellites

Question 50

Three ways a carrier can be varied to transmit intelligence

Answer 50

Vary carrier amplitude/AM, frequency, or phase

Question 51

Two household remote controls + media/frequency

Answer 51

TV remote control (infrared), garage door opener (radio—VHF or UHF)

Question 52

How is radio astronomy used to map stars?

Answer 52

Stars (suns) radiate radio waves that can be received by directional antennas that can record azimuth and elevation to plot star positions

Question 53

Communication field segment of interest & why

Answer 53

I’m interested in RF and wireless technologies because they power modern communication like mobile networks and IoT.

Question 54

If ELF–microwave spectrum is full, how to add capacity

Answer 54

Use optical spectrum (infrared, visible) Implement spread spectrum or UWB Develop quantum or satellite-based systems Use spectrum sharing and compression

Question 55

Speed of light conversions

Answer 55

Meters/second: 3 × 10⁸ m/s Feet/μs: ≈ 984 ft/μs Inches/ns: ≈ 11.8 in/ns

Question 56

Five real-life communication applications not mentioned

Answer 56

Smart watches Smart speakers (e.g., Alexa) RFID for inventory Car-to-car communication (V2V) Drone-based delivery systems

Question 56

Compare speed of light vs sound

Answer 56

Light is ~1,000,000× faster than sound. Example: A lightning flash is seen before thunder is heard.

Question 57

Wireless product in UHF band – how to choose & license

Answer 57

Check FCC (US) or NTC (PH) frequency allocations Apply for a license or use ISM bands (unlicensed) Avoid interference by checking spectrum databases

Question 58

How does the paper cup + string phone work?

Answer 58

Sound vibrations travel through the taut string, vibrating the other cup, recreating the sound—mechanical wave transmission.

Question 59

example of analog technology

Answer 59

radio

Question 60

widely process in the communication sytem. a very high frequency

Answer 60

modulation

Question 61

wired comm

Answer 61

parallel, twisted, coaxial, optical

Question 62

changes on signal freq. can be linear and non

Answer 62

distortion

Question 63

signal strength reduction over long distance using amplifiers or repeater

Answer 63

attenuation

Question 64

interference form nearby signal electron motion in conductor

Answer 64

external internal

Question 65

transmit data as electronic signals with varying frequency amplitude

Answer 65

analog comm

Question 66

not a type of comm system based on signal

Answer 66

parallel

Question 67

it eliminates noise

Answer 67

freq. mod

Question 68

immune to noise, dependent on freq

Answer 68

phase

Question 69

signal carrying many channels, wide bandwith

Answer 69

broadband

Question 70

in digital tech, data is generated

Answer 70

high and low

Question 71

element of comm system receive electromagnetic waves

Answer 71

antenna

Question 72

supremosing it on high freq keeping its constant, transmitting with radio wave

Answer 72

AM

Question 73

convert physical signals. one from energy to another

Answer 73

transducer

Question 74

to increase amplitude of a transmitted signal

Answer 74

amplifier

Question 75

how internal noise can be minimized

Answer 75

digital techno

Question 76

both satellite and terrestrial

Answer 76

digital radio

Question 77

to amplify and retransmit

Answer 77

repeater

Question 78

networks of computers transmit over geographic area such as college campus

Answer 78

metropolitan

Question 79

recovering an original signal

Answer 79

demodulation

Question 80

converts individual baseband signal

Answer 80

multiplexer

Question 81

regenates individual baseband signals

Answer 81

demultiplexer

Question 82

seperated the orig message

Answer 82

demodulator

Question 83

main categories of comm channel

Answer 83

wire and wirelesa