NAVEDTRA 14189A, NEETS Mod. 17, Ch. 2 Flashcards Preview

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Flashcards in NAVEDTRA 14189A, NEETS Mod. 17, Ch. 2 Deck (29)
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1

What is the principle use of the continuous wave?

Radiotelegraphy

2

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

Antenna

3

What is power the product of?

Current and Voltage

4

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?

Subharmonic

5

What are special power amplifiers that multiply the input frequency?

Frequency multipliers

6

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

Suppression

7

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

Single-sideband

8

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?

SSB

9

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

ISB

10

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

Reception, selection, detection, and reproduction

11

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

Reception

12

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?

Selection

13

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

Detection

14

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

Reproduction

15

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

Sensitivity

16

What is the limiting factor of sensitivity?

Noise

17

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

Selectivity

18

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

Fidelity

19

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

Ganged tuning

20

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

Discriminator and Limiter

21

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

Discriminator

22

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

Fading

23

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

Reverse AGC

24

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

Frequency response

25

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

3,000 hertz

26

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

300 hertz

27

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

Automatic Frequency Control

28

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

Squelch

29

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

Frequency synthesis