Amplitude modulation: Difference between revisions
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== title: Amplitude Modulation (AM) description: published: true date: 2022-07-25T07:54:08.319Z tags: modes, am, amplitude modulation editor: markdown dateCreated: 2022-07-24T12:27:11.526Z ==--> | == title: Amplitude Modulation (AM) description: published: true date: 2022-07-25T07:54:08.319Z tags: modes, am, amplitude modulation editor: markdown dateCreated: 2022-07-24T12:27:11.526Z ==--> | ||
Amplitude Modulation (AM) is a mode for transmitting voice over the air. It consists of a HF carrier whose amplitude is varied (''i.e.'' modulated) in proportion to the transmitted audio signal (''i.e.'' the [[theory/baseband|baseband]] signal). Spectrally, an AM signal contains this carrier and two [[theory/sidebands|sidebands]] above and below the carrier; the upper sideband is a frequency-shifted copy of the baseband signal, while the lower sideband is a frequency-shifted and frequency-inverted copy of the baseband signal. While it was the first audio mode ever developed, and was the first audio mode used on amateur radio, AM is not very popular in the present day because [[modes/fm|FM]] is more resilient against interference on [[ | Amplitude Modulation (AM) is a mode for transmitting voice over the air. It consists of a HF carrier whose amplitude is varied (''i.e.'' modulated) in proportion to the transmitted audio signal (''i.e.'' the [[theory/baseband|baseband]] signal). Spectrally, an AM signal contains this carrier and two [[theory/sidebands|sidebands]] above and below the carrier; the upper sideband is a frequency-shifted copy of the baseband signal, while the lower sideband is a frequency-shifted and frequency-inverted copy of the baseband signal. While it was the first audio mode ever developed, and was the first audio mode used on amateur radio, AM is not very popular in the present day because [[modes/fm|FM]] is more resilient against interference on [[The Practicalities of VHF and UHF|VHF/UHF]] and [[modes/ssb|SSB]] is more spectrally efficient, saving space on the narrow [[bands/hf|HF]] bands on which it is used. | ||
Revision as of 11:57, 13 September 2022
Amplitude Modulation (AM) is a mode for transmitting voice over the air. It consists of a HF carrier whose amplitude is varied (i.e. modulated) in proportion to the transmitted audio signal (i.e. the baseband signal). Spectrally, an AM signal contains this carrier and two sidebands above and below the carrier; the upper sideband is a frequency-shifted copy of the baseband signal, while the lower sideband is a frequency-shifted and frequency-inverted copy of the baseband signal. While it was the first audio mode ever developed, and was the first audio mode used on amateur radio, AM is not very popular in the present day because FM is more resilient against interference on VHF/UHF and SSB is more spectrally efficient, saving space on the narrow HF bands on which it is used.