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单词 frequency modulation
释义

frequency modulation


frequency modulation

n. Abbr. FM The encoding of a carrier wave by variation of its frequency in accordance with an input signal.

frequency modulation

n (Telecommunications) a method of transmitting information using a radio-frequency carrier wave. The frequency of the carrier wave is varied in accordance with the amplitude and polarity of the input signal, the amplitude of the carrier remaining unchanged. Abbreviation: FM Compare amplitude modulation

FM

1. frequency modulation: a method of impressing a signal on a radio carrier wave by varying the frequency of the carrier wave. 2. a system of radio broadcasting by means of frequency modulation. Compare AM.

Fm

Chem. Symbol. fermium.

fm.

1. fathom. 2. from.

frequency modulation

A method of radio broadcasting in which the frequency of the wave that carries the sound signal changes to reflect the various sounds that are to be reproduced, while the amplitude of the wave remains the same. Frequency modulation reduces static in radio transmission. Compare amplitude modulation.
Thesaurus
Noun1.frequency modulation - modulation of the frequency of the (radio) carrier wavefrequency modulation - modulation of the frequency of the (radio) carrier waveFMmodulation - (electronics) the transmission of a signal by using it to vary a carrier wave; changing the carrier's amplitude or frequency or phase
Translations
modulation de fréquence

frequency modulation


frequency modulation:

see modulationmodulation,
in communications, process in which some characteristic of a wave (the carrier wave) is made to vary in accordance with an information-bearing signal wave (the modulating wave); demodulation is the process by which the original signal is recovered from the wave
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; radioradio,
transmission or reception of electromagnetic radiation in the radio frequency range. The term is commonly applied also to the equipment used, especially to the radio receiver.
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.

Frequency Modulation

 

a method of modulating oscillations, in which the frequency of the high-frequency carrier oscillations is varied over time according to a law that corresponds to the signal being transmitted. A feature of frequency modulation is its high immunity to noise. Frequency modulation is used for high-quality transmission of information: in radio broadcasting (in the very-high-frequency band), for the audio signal of television programs, in voice-frequency telegraphy, in radiotelephone communications, and in other fields.

frequency modulation

[′frē·kwən·sē ‚mäj·ə‚lā·shən] (communications) Modulation in which the instantaneous frequency of the modulated wave differs from the carrier frequency by an amount proportional to the instantaneous value of the modulating wave. Abbreviated FM.

Frequency Modulation

(communications)(FM) A method of encoding data by varying thefrequency of a constant amplitude carrier signal.

Contrast Amplitude Modulation.

frequency modulation

(1) An earlier magnetic disk encoding method that places clock bits onto the medium along with the data bits. It was superseded by MFM and RLL.

(2) Varying the frequency of the waves of a carrier in order to transmit analog or digital data. Frequency modulation (FM) is widely used in audio transmission, not only for its namesake FM radio, but for the audio channels in television. See modulation and carrier.


Vary the Angle
In FM modulation, the frequency of the carrier wave is varied by the incoming signal. In this example, the modulating wave implies an analog signal.







Digital Frequency Shift Keying (FSK)
For digital signals, frequency shift keying (FSK) uses two frequencies for 0 and 1 as in this example.








A Sad Tale of FM Origins


FM radio was invented in the early 1930s by Edwin Howard Armstrong, who years earlier had made a fortune selling RCA his amplifier technology. When he asked RCA to license his FM in 1933, RCA turned it down and pursued its own research. Seven years later, RCA offered him USD $1 million for outright purchase, but Armstrong declined. He was angry at the long hiatus and thought the offer too low. Later, Armstrong sued for patent infringement when he discovered RCA was using his technology, but RCA's legal tactics kept him at bay for so many years that the patents expired. Fighting the company also depleted his wealth. In 1954, Armstrong wrote a note to his wife, walked over to his bedroom window and jumped 13 stories to his death. Eventually, his wife received millions in back royalties from the company.
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See FIDE Master

frequency modulation


Related to frequency modulation: phase modulation, amplitude modulation
  • noun

Synonyms for frequency modulation

noun modulation of the frequency of the (radio) carrier wave

Synonyms

  • FM

Related Words

  • modulation
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更新时间:2024/12/22 21:14:06