NAVEDTRA 14189A, NEETS Mod. 17, Ch. 2 Flashcards
What is the principle use of the continuous wave?
Radiotelegraphy
A cw transmitter requires four essential components. These are a generator, amplifier, keyer, and what else?
Antenna
What is power the product of?
Current and Voltage
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
What are special power amplifiers that multiply the input frequency?
Frequency multipliers
What is the elimination of the undesired portions of the signal?
Suppression
What type of transmission is the most common communications mode used today?
Single-sideband
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
What is used extensively in naval communications to expand our traffic capabilities?
ISB
What four basic functions must a receiver perform in order to be useful?
Reception, selection, detection, and reproduction
What occurs when a transmitted electromagnetic wave passes through the receiver antenna and induces a voltage in the antenna?
Reception
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
What is the action of separating the low (audio) frequency intelligence from the high (radio) frequency carrier?
Detection
What is the action of converting the electrical signals to sound waves?
Reproduction
What property is defined by the ability of a receiver to reproduce weak signals?
Sensitivity
What is the limiting factor of sensitivity?
Noise
What is the degree of distinction made by the receiver between the desired signal and unwanted signals?
Selectivity
What property of a receiver is its ability to accurately reproduce, in its output, the signal that appears at its input?
Fidelity
What is the process used to tune two or more circuits with a single control?
Ganged tuning
What are the only two fundamental sections of the fm receiver that are electrically different from the AM receiver?
Discriminator and Limiter
Which circuit in FM circuits is designed to respond to frequency shift variations?
Discriminator
What is the variation in signal strength called at the receiver antenna?
Fading
Fading
What is an AGC voltage that is used to cause degeneration by driving the amplifiers toward cutoff referred to as?
Reverse AGC
Which audio amplifier property determines the degree of amplification provided to different frequencies in the sound spectrum?
Frequency response
Treble tones are defined as the audio frequencies above approximately what frequency?
3,000 hertz
Bass tones are defined as the audio frequencies below approximately what frequency?
300 hertz
Which circuits are used in situations where you must accurately control the frequency of an oscillator by some external signal?
Automatic Frequency Control
Which circuit cuts off the output of a receiver when there is no input?
Squelch
What is a signal-producing process through heterodyning and frequency selection?
Frequency synthesis