Frequency Modulation


Frequency Modulation (FM) is a method of transmitting information by altering the frequency of a carrier wave in accordance with the amplitude of the input signal. In this technique, the carrier wave’s amplitude remains constant while its frequency changes with the input signal’s waveform. FM is widely used in radio broadcasting, wireless communication, and audio signal transmission.


The phonetics of the keyword “Frequency Modulation” are:Frequency: /ˈfriːkwənsi/Modulation: /ˌmɒdʒʊˈleɪʃən/

Key Takeaways

  1. Frequency Modulation (FM) is a modulation technique where the frequency of the carrier wave is varied in accordance with the amplitude of the input signal.
  2. FM provides improved signal-to-noise ratio, better sound quality, and greater immunity to noise and interference as compared to Amplitude Modulation (AM).
  3. FM is widely used in various applications such as radio broadcasting, telecommunications, and entertainment systems due to its superior performance and higher efficiency.


Frequency Modulation (FM) is a significant technology term due to its broad influence in the realms of communication and broadcasting.

It is a modulation technique where the frequency of the carrier signal is altered in accordance with the variations in the amplitude of the input signal.

This process enhances signal transmission, enabling it to withstand external interferences and noise, thus leading to improved signal quality and reduced signal loss.

FM is extensively used in radio broadcasting, television audio transmission, two-way radios, and other wireless communication systems, playing a vital role in our day-to-day lives by ensuring reliable, efficient, and high-fidelity communication.


Frequency Modulation (FM) serves as a crucial technology in the realm of telecommunications, and its purpose primarily revolves around the transmission of data over long distances with higher efficiency and minimal loss of quality. Invented by Edwin H. Armstrong in 1933, FM revolutionized the world of radio broadcasting, enabling listeners to experience reduced noise and improved audio fidelity.

This innovative method of communication functions by altering the carrier wave frequency in proportion to the amplitude variations of the input signal. Consequently, FM allows the signal’s information to be embedded and transmitted effectively via the simultaneous encoding of frequency changes. Aside from the domain of radio broadcasting, FM is also widely utilized for various communication applications such as data transmission services, emergency services, vehicle-to-vehicle communication, and aviation communication.

Additionally, FM synthesizers in the music industry are responsible for creating a plethora of unique sounds and assisting with the emulation of different musical instruments. The impressive resistance offered by FM to noise and interference aids in maintaining the information’s integrity during transmission, which ultimately results in higher quality and more reliable communication. Overall, Frequency Modulation has spearheaded the development of contemporary telecommunications systems, paving the way for enhanced global connectivity.

Examples of Frequency Modulation

Radio Broadcasting: Frequency Modulation (FM) is widely used in radio broadcasting for transmitting high-quality audio signals over the airwaves. FM radio stations operate in the VHF (Very High Frequency) range, typically between 88 MHz and 108 MHz. Compared to AM (Amplitude Modulation) radio, FM provides better sound quality and is less susceptible to interference and noise caused by weather conditions or other electromagnetic sources.

Wireless Microphones: FM is also utilized in wireless microphone systems, which are commonly used in live events, stage productions, and television broadcasts. By modulating the audio signals with FM, wireless microphones can ensure the sound quality remains high while transmitting over an extended range. It also helps to mitigate interference from other electronic devices or nearby wireless systems.

Land Mobile Radio Systems: Two-way radio communication services, such as police, emergency services, and private business communication networks, rely on FM technology for clear and reliable communication. These land mobile radio systems operate in various frequency bands, such as VHF and UHF (Ultra High Frequency), and utilize FM to provide voice communications with minimal distortion and noise. This enables first responders and other professionals to maintain effective communication during critical situations.

Frequency Modulation FAQ

What is Frequency Modulation?

Frequency Modulation (FM) is a modulation technique where the frequency of a carrier wave is varied according to the amplitude of the modulating signal. It is commonly used in radio broadcasting, telecommunications, and other wireless communication systems as it provides better sound quality and noise immunity compared to Amplitude Modulation (AM).

How does Frequency Modulation work?

In Frequency Modulation, the frequency of the carrier wave is altered based on the amplitude of the input signal or message. When the input signal amplitude is higher, the carrier frequency increases, and when the input signal amplitude is lower, the carrier frequency decreases. This results in the frequency of the carrier wave being directly proportional to the amplitude of the modulating signal, allowing it to carry the information through the transmission medium.

What are the advantages of Frequency Modulation?

1. Better noise immunity: FM signals are less susceptible to noise and interference than AM signals, providing clearer, high-quality audio transmission.
2. Improved signal-to-noise ratio: In FM systems, increasing the transmitted power can significantly improve the signal-to-noise ratio, ensuring better reception at the receiving end.
3. Less distortion: FM systems have a lower non-linear distortion compared to AM systems, resulting in better audio quality and clarity.
4. Larger bandwidth: FM signals have a wider frequency range, which allows for a higher amount of information to be transmitted.

What are the disadvantages of Frequency Modulation?

1. Larger bandwidth requirement: FM requires a larger bandwidth compared to AM, which may lead to crowding in the frequency spectrum and limit the number of channels that can be accommodated.
2. More complex equipment: To transmit and receive FM signals, more complex equipment is required compared to AM systems.
3. Limited range: FM signals can experience a limited range due to the constraint of line-of-sight transmission. In hilly or densely populated areas, the signal may get obstructed by physical barriers.

What are the applications of Frequency Modulation?

1. FM radio broadcasting: FM radio is the most popular application of Frequency Modulation, providing high-quality audio broadcasting to listeners.
2. Television audio transmission: The audio signal in analog TV broadcasting systems uses FM for improved audio quality.
3. Wireless communications: FM is widely used in various wireless communication systems, such as two-way radio, mobile communication, and data communication.
4. Satellite communication: FM is also used in satellite communication systems to provide clear voice and data transmission across long distances.

Related Technology Terms

  • Carrier Wave
  • Modulation Index
  • Bandwidth
  • FM Transmitter
  • Demodulation

Sources for More Information


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