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Guilherme Mazui

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What is the Difference Between AM and FM?

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The main difference between AM (Amplitude Modulation) and FM (Frequency Modulation) radio lies in how the carrier wave is modulated or altered to transmit the audio signal. In AM radio, the amplitude or overall strength of the signal is varied, while in FM radio, the frequency (the number of times each second that the current changes direction) of the carrier signal is varied.

Here are some key differences between AM and FM radio:

  • Spectrum Range: AM radio ranges from 535 to 1705 kilohertz, whereas FM radio ranges in a higher spectrum from 88 to 108 megahertz.
  • Sound Quality: FM radio typically sounds better than AM radio due to its wider bandwidth and less susceptibility to interference.
  • Broadcast Range: AM radio has a longer range than FM radio, which means FM signals have a more limited coverage area.
  • Audio Transmission: AM radio usually broadcasts in mono, making it sufficient for talk radio, while FM radio can transmit in stereo, making it ideal for music.

In summary, AM radio uses amplitude modulation to transmit audio signals, resulting in a longer range but lower sound quality compared to FM radio, which uses frequency modulation and offers better sound quality and performance within a shorter range.

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  • What is the Difference Between AM and FM?
  • Comparative Table: AM vs FM

    • Comparative Table: AM vs FM

    Here is a table comparing the differences between AM (Amplitude Modulation) and FM (Frequency Modulation):

    Feature AM (Amplitude Modulation) FM (Frequency Modulation)
    Definition The amplitude of the carrier wave varies according to the signal that carries information. The frequency of the carrier wave is modified according to the signal that carries information.
    Invention Developed in the mid-1870s. Developed in 1930 by Edwin Armstrong.
    Radio Wave Called a carrier wave, with frequency and phase remaining the same. Called a carrier wave, but amplitude and phase remain the same.
    Sound Quality Poor sound quality, but can transmit longer distances. Higher bandwidth with better sound quality.
    Frequency Range Varied from 535 to 1705 kHz. 88 to 108 MHz in the higher spectrum.
    Susceptibility to Noise More susceptible to noise. Less susceptible to noise.

    AM radio signals have a larger range but poorer sound quality, while FM radio signals have a smaller range but offer better sound quality.

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    Guilherme Mazui

    Guilherme Mazui is graduated in journalism from the Federal University of Minas Gerais (UFMG) and a master's degree in Communication from the University of São Paulo (USP). In addition, he has experience in advertising writing and has worked as a content editor in several companies.