Chapter 1 - Tomasi

Question 1

Who discovered the electromagnetic waves?

Answer 1

Heinrich Hertz

Question 2

Who discovered the radio waves?

Answer 2

Heinrich Hertz

Question 3

Who developed the superheterodyne radio receiver?

Answer 3

Major Edwin Armstrong

Question 4

Who invented and demonstrated the television?

Answer 4

Vladimir Zworykin

Question 5

Who patented the wide-band frequency modulation?

Answer 5

Major Edwin Armstrong

Question 6

What does FCC stands for?

Answer 6

Federal Communications Commission

Question 7

________ was created to regulate telephone, radio and television broadcasting.

Answer 7

FCC

Question 8

What is the FM signal range?

Answer 8

88MHz to 108MHz

Question 9

What country launched the world’s first satellite and what is its name?

Answer 9

Russia, Sputnik

Question 10

These are time-varying voltage or current waves.

Answer 10

Analog signals

Question 11

Is sometimes referred to as a power loss.

Answer 11

Attenuation

Question 12

Is sometimes referred to as a ________ , If Pout = Pin, the absolute power gain is 1, and the dB power gain is 0 dB.

Answer 12

Unity Power Gain

Question 13

Are voltages or currents that change in discrete steps or levels.

Answer 13

Digital Signals

Question 14

In 1876, Alexander Graham Bell and Thomas A. Watson were the first to successfully transfer human conversation over a crude metallic- wire communications systems using this device.

Answer 14

Telephone

Question 15

A collection of one or more electronic devices or circuits that converts the original source information to a form more suitable for transmission over a particular transmission medium.

Answer 15

Transmitter

Question 16

Provides a means of transporting signals between a transmitter and a receiver.

Answer 16

Medium

Question 17

A collection of electronic devices and circuits that accepts the transmitted signals fro the transmission medium and then converts those signals back to their original form.

Answer 17

Reciever

Question 18

Is any unwanted electrical signals that interfere with the information signal.

Answer 18

System Noise

Question 19

Because it is often impractical to propagate information signals over standard transmission media, it is often necessary to modulate the source information onto a higher-frequency analog signal called a ______.

Answer 19

Carrier

Question 20

The process of changing one or more signals of the analog carrier in proportion with the information signal.

Answer 20

Modulation

Question 21

A modulation technique where the information signal is analog and the amplitude (V) of the carrier is varied proportional to the information signal.

Answer 21

AM

Question 22

A modulation technique where the information signal is analog and the frequency (f) of the carrier is varied proportional to the information signal.

Answer 22

FM

Question 23

A modulation technique where the information signal is analog and the phase () of the carrier is varied proportional to the information signal.

Answer 23

PM

Question 24

A modulation technique where the information signal is digital and that amplitude (V) of the carrier is varied proportional to the information signal.

Answer 24

Amplitude Shift Keying ( ASK )

Question 25

A modulation technique where the information signal is digital and the frequency (f) of the carrier is varied proportional to the information signal.

Answer 25

Frequency Shift Keying ( FSK )

Question 26

A modulation technique where the information signal is digital and the phase () of the carrier is varied proportional to the information signal.

Answer 26

Phase Shift Keying ( PSK )

Question 27

Modulation is performed in a transmitter by a circuit called \_\_\_\_\_\_\_\_.

Answer 27

Modulator

Question 28

The reverse process of modulation and converts the modulated carrier back to the original information

Answer 28

Demodulation

Question 29

Is an international agency in control of allocating frequencies and services within the overall frequency spectrum.

Answer 29

International Telecommunications Union ( ITU )

Question 30

Are signals in the 30Hz to 300Hz range and include ac power distribution signals (60Hz) and low frequency telemetry signals.

Answer 30

Extremely Low Frequencies ( ELF )

Question 31

Are signals in the 300Hz to 3000Hz range and include frequencies generally associated with human speech.

Answer 31

Voice Frequencies ( VF )

Question 32

Are signals in the 3kHz to 30kHz range which include the upper end of the human hearing range.

Answer 32

Very Low Frequencies ( VLF )

Question 33

Are signals in the 30kHz to 300kHz range and are used primarily for marine and aeronautical navigation.

Answer 33

Low Frequencies ( LF )

Question 34

Are signals in the 300kHz to 3MHz range and are used primarily for commercial AM radio broadcasting (535kHz-1605kHz).

Answer 34

Medium Frequencies ( MF )

Question 35

Are signals in the 3MHz to 30MHz range and are often referred to as short waves. Used for most two-way radio communications.

Answer 35

High Frequencies ( HF )

Question 36

Are signals in the 30MHz to 300MHz range and are used for mobile radio, marine and aeronautical communications, commercial FM broadcasting (88 to 108MHz) and commercial TV broadcasting of Ch 2 to 13 (54MHz to 216MHz).

Answer 36

Very High Frequencies ( VHF )

Question 37

Are signals in the 300MHz to 3GHz range and are used by commercial television broadcasting of channels 14 to 83, land mobile communications services, cellular telephones, certain radar and navigation systems, and microwave and satellite radio systems.

Answer 37

Ultrahigh Frequencies ( UHF )

Question 38

Are signals in the 3GHz to 30GHz range and include the majority of the frequencies used for microwave and satellite radio communications systems.

Answer 38

Super High Frequencies ( SHF )

Question 39

Are signals in the 30GHz to 300GHz range and are seldom used for radio communications except in very sophisticated, expensive, and specialized applications.

Answer 39

Extremely High Frequencies ( EHF )

Question 40

Are signals in the 0.3THz to 300THz range and are not generally referred to as radio waves. Used in heat seeking guidance systems, electronic photography, and astronomy.

Answer 40

Infrared

Question 41

Includes electromagnetic frequencies that fall within the visible range of humans (0.3PHz to 3PHz).

Answer 41

Visible Light

Question 42

The two most significant limitations on the performance of a communications system are \_\_\_\_\_\_\_\_and \_\_\_\_\_\_\_\_.

Answer 42

Noise and Bandwidth

Question 43

The difference between the highest and lowest frequencies contained in the information.

Answer 43

The difference between the highest and lowest frequencies contained in the information.

Question 44

Any undesirable electrical energy that falls within the passband of the signal.

Answer 44

Electrical Noise

Question 45

Noise present regardless of whether there is a signal present or not.

Answer 45

Uncorrelated Noise

Question 46

Noise that is generated outside the device or circuit.

Answer 46

External Noise

Question 47

Noise that is naturally occurring electrical disturbances that originate within Earth’s atmosphere.

Answer 47

Atmospheric Noise

Question 48

Atmospheric noise is commonly called ____________ .

Answer 48

Static Electricity

Question 49

Noise consists of electrical signals that originate from outside Earth’s atmosphere and is sometimes called deep-space noise.

Answer 49

Extraterrestrial Noise

Question 50

Extraterrestrial noise is sometimes called ____________ .

Answer 50

Deep-Space Noice

Question 51

Noise generated directly from the sun’s heat.

Answer 51

Solar Noise

Question 52

Noise sources that are continuously distributed throughout the galaxies.

Answer 52

Cosmic Noise

Question 53

Noise that is produced by mankind.

Answer 53

Man-made Noise

Question 54

Electrical interference generated within a device or circuit.

Answer 54

Internal Noise

Question 55

Noise caused by the random arrival of carriers (holes and electrons) at the output element of an electronic device.

Answer 55

Shot Noise

Question 56

Any modification to a stream of carriers as they pass from the input to the output of a device produces an irregular, random variations.

Answer 56

Transit-time Noise

Question 57

Associated with the rapid and random movement of electrons within a conductor due to thermal agitation.

Answer 57

Thermal Noise

Question 58

A form of internal noise that is correlated (mutually related) to the signal and cannot be present in a circuit unless there is a signal. “ no signal, no noise! “

Answer 58

Correlated Noise

Question 59

Occurs when unwanted harmonics of a signal are produced through nonlinear amplification (nonlinear mixing).

Answer 59

Harmonic Distortion

Question 60

Another name for harmonic distortion.

Answer 60

Amplitude Distortion

Question 61

A form of external noise and as the name implies it means to disturb or detract form.

Answer 61

Interference

Question 62

The ratio of the signal power level to the noise power level.

Answer 62

Signal-to-Noise Power Ratio ( S/N )

Question 63

Figures of merit used to indicate how much the signal- to-noise ratio deteriorates as a signal passes through a circuit or series of circuits

Answer 63

Noise Factor ( F ) and Noise Figure ( NF )

Question 64

What is the formula for noise factor?

Answer 64

Question 65

What is the formula for noise figure?

Answer 65