Definition

1. Noun:
   • A method of encoding information in a carrier wave by varying its instantaneous frequency: "Frequency modulation" is a specific technique in telecommunications and signal processing where the frequency of a carrier wave is changed in proportion to the amplitude of a modulating signal (e.g., an audio signal). This contrasts with amplitude modulation (AM), where the amplitude is varied.

Usage Examples

• Noun:
  • FM radio broadcasting uses frequency modulation to provide high-fidelity sound.
  • The engineer explained that the signal's clarity was due to the use of frequency modulation.

Advanced Usage

• "Narrowband frequency modulation (NBFM)": A type of FM where the modulation index is small, resulting in a narrow bandwidth. Commonly used in two-way radio communications.

  • The walkie-talkies use narrowband frequency modulation for clear voice transmission over short distances.

• "Wideband frequency modulation (WBFM)": A type of FM with a large modulation index, resulting in a wider bandwidth and higher fidelity. Used in FM radio broadcasting.

  • Commercial music stations broadcast using wideband frequency modulation.

Variants and Related Words

• FM (abbreviation, noun): The common abbreviation for "frequency modulation."

  • I prefer listening to music on FM stations.

• Modulate (verb): To vary the properties of a wave. Frequency modulation is one type of modulation.

  • The circuit is designed to modulate the carrier signal.

• Demodulation (noun): The process of extracting the original information signal from a modulated carrier wave. An FM receiver performs demodulation.

  • Demodulation is a crucial step in recovering the audio from the FM signal.

Synonyms

• Angle modulation: A broader category of modulation that includes both frequency modulation (FM) and phase modulation (PM), as both vary the angle of the carrier wave.

Related Phrases and Technical Terms

• Frequency deviation: In FM, this is the maximum difference between the instantaneous frequency of the modulated wave and the carrier frequency. It is a key parameter.

  • The allowed frequency deviation determines the signal's bandwidth.

• Capture effect: A phenomenon in FM reception where the receiver locks onto the stronger of two signals on the same frequency, suppressing the weaker one.

  • The capture effect in FM can sometimes eliminate interference from a distant station.

Noun

1. modulation of the frequency of the (radio) carrier wave