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ITC EXAM 2019 > NAVEDTRA 14189A, NAVY ELECTRICITY AND ELECTRONICS TRAINING SERIES. MODULE 17-RADIO-FREQUENCY COMMUNICATIONS PRINCIPLES > Flashcards

NAVEDTRA 14189A, NAVY ELECTRICITY AND ELECTRONICS TRAINING SERIES. MODULE 17-RADIO-FREQUENCY COMMUNICATIONS PRINCIPLES Flashcards

1
Q

What is the principle use of the continuous wave?

A

Radiotelegraphy

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2
Q

A cw transmitter requires four essential components. These are a generator, amplifier, keyer, and what else?

A

Antenna

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3
Q

What is power the product of?

A

Current and Voltage

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4
Q

What refers to a sine wave quantity (for example, an oscillator output) that has a frequency that is a submultiple of the frequency of some other sine wave quantity it helped make?

A

Subharmonic

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5
Q

What are special power amplifiers that multiply the input frequency?

A

Frequency multipliers

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6
Q

What is the elimination of the undesired portions of the signal?

A

Suppression

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7
Q

What type of transmission is the most common communications mode used today?

A

Single-sideband

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8
Q

What is generally used whenever special voice communications circuits are necessary between shore activities or between ships and shore activities because it is less susceptible to atmospheric interference than amplitude modulation?

A

SSB

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9
Q

What is used extensively in naval communications to expand our traffic capabilities?

A

ISB

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10
Q

What four basic functions must receiver perform in order to be useful?

A

Reception, selection, detection, and reproduction

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11
Q

What occurs when a transmitted electromagnetic wave passes through the receiver antenna and induces a voltage in the antenna?

A

Reception

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12
Q

What is the ability of the receiver to select a particular frequency of a station from all other station frequencies appearing at the antenna of the receiver?

A

Selection

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13
Q

What is the action of separating the low (audio) frequency intelligence from the high (radio) frequency carrier?

A

Detection

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14
Q

What is the action of converting the electrical signals to sound waves?

A

Reproduction

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15
Q

What property is defined by the ability of a receiver to reproduce weak signals?

A

Sensitivity

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16
Q

What is the limiting factor of sensitivity?

A

Noise

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17
Q

What is the degree of distincition made by the receiver between the desired signal and unwanted signals?

A

Selectivity

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18
Q

What property of a receiver is its ability to accurately reproduce, in its output, the signal that appears at its input?

A

Fidelity

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19
Q

What is the process used to tune two or more circuits with a single control?

A

Ganged tuning

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20
Q

What are the only two fundamental sections of the fm receiver that are electrically different from the AM receiver?

A

Discriminator and Limiter

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21
Q

Which circuit in FM circuits is designed to respond to frequency shift variations?

A

Discriminator

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22
Q

What is the variation in signal strength called at the receiver antenna?

A

Fading

23
Q

What is an AGC voltage that is used to cause degradation by driving the amplifiers toward cutoff referred to as?

A

Reverse AGC

24
Q

Which audio amplifier property determines the degree of amplification provided to different frequencies in the sound spectrum?

A

Frequency response

25
Q

Treble tones are defined as the audio frequencies above approximately what frequency?

A

3,000 hertz

26
Q

Bass tones are defined as the audio frequencies below approximately what frequency?

A

300 hertz

27
Q

Which circuits are used in simulations where you must accurately control the frequency of an oscillator by some external signal?

A

Automatic Frequency Control

28
Q

Which circuit cuts off the output of a receiver when there is no input?

A

Squelch

29
Q

What is a signal-producing process through heterodyning and frequency selection?

A

Frequency synthesis

30
Q

Which year was the first artificial satellite placed in orbit by the Russians?

A

1957

31
Q

Score was the first satellite with the primary purpose of communications by the US in which year?

A

1958

32
Q

Which year was the first regular satellite communications service used by the Navy?

A

1960

33
Q

Which year was the Defense Communications Satellite Program (DCSP) initiated by the Secretary of Defense?

A

1962

34
Q

Which type of satellite only reflects received audio signals back to earth?

A

Passive

35
Q

What amplifies signals received and then retransmits them back to earth?

A

Repeater

36
Q

In general terms, an orbit is either elliptical or which other shape?

A

Circular

37
Q

What is a period of orbit that approaches that of the earth called?

A

Near Synchronous

38
Q

All satellites orbit the earth in which type of orbits?

A

Elliptical

39
Q

What is the point in the orbit called when it is the greatest distance from the center of the earth?

A

Apogee

40
Q

What is the angle between the equatorial plane of the earth and the orbital plane of the satellite called?

A

Angle of inclination

41
Q

A satellite orbiting in any plane not identical with the equatorial plane is in which type of orbit?

A

Inclined

42
Q

Which type of orbit is defined by a satellite orbiting in a plane that coincides with the equatorial plane of the earth?

A

Equatorial

43
Q

A satellite in a circular orbit at a height of approximately how many nautical miles above the earth is in a synchronous orbit?

A

19,300

44
Q

A satellite in a circular orbit from approximately 2,000 miles to how many miles above the earth is considered to be in a medium altitude orbit?

A

12,000

45
Q

About how many solar cells mounted on the surface of the satellite newer communications satellites have?

A

32,000

46
Q

Generally speaking, how many sizes of parabolic-type antennas are currently in use at earth terminal sites?

A

Three

47
Q

Depending on the type used and the operational requirements, transmitters used in earth terminals have output power capabilities that vary from 10 watts to how many kilowatts?

A

20

48
Q

Which table provides the coordinates of a satellite or a celestial body at specific times during a given period?

A

Ephemeris

49
Q

What is the period of time called for one earth terminal to yield control to another as a satellite moves out of its area of coverage?

A

Hand over

50
Q

The smallest terminal in the defense communication systems network has effectively an 18-foot antenna and weighs how many pounds?

A

19,500

51
Q

Which year did the Department of the Navy establish the Naval Space Command?

A

1983

52
Q

Which year was the first DSCS Phase III satellite launched into orbit?

A

1984

53
Q

Which publication was written to concisely explain the role of the Navy in the Defense Communications Satellite Program?

A

NTP-2

54
Q

What is the zone called where the satellite can be seen by both the up- and the down-link earth terminals?

A

Zone of mutual visibility

ITC EXAM 2019 (18 decks)

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