• Abbreviation of frequency modulation. A form of modulation in which the instantaneous frequency of a sine wave carrier is varied above and below the center frequency by a modulating signal. The center frequency is that of the un modulated carrier, and its variation is proportional to the in stantaneous value of the modulating signal. It is a form of angle modulation, and is used, for instance, for broadcasting. This contrasts with AM, where the amplitude of the carrier wave and its sidebands are modulated, or varied, but its frequency is kept constant, or with PM, where the phase angle of the carrier wave is varied.
  • chemical symbol for fermium
    (written as Fm)
  • abbreviation for femtometer
    (written as fm)
  • 10-15 meter. It is a unit of measurement of length. Its abbreviation is fm.

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