Amplitude modulation is a signal processing technique where the amplitude of a higher-frequency carrier signal is varied proportionally by a lower-frequency modulating signal. The output contains the original carrier frequency plus upper and lower sidebands at (f_carrier + f_modulator) and (f_carrier - f_modulator). Parameters include modulation index (depth of amplitude variation), carrier frequency, and modulator frequency. The mechanism of persistence: hardware AM uses analog multipliers or diode modulators; digital AM implements sample-by-sample multiplication. In communications, AM encodes information in amplitude variations; in audio synthesis, AM produces characteristic timbral effects. [formal: modulatio amplitudinis | substrate: mind | horizon: a moment | explicit: yes | epoch: 0.01]
Accepted ontology entry
amplitude-modulation
Amplitude modulation is a signal processing technique where the amplitude of a higher-frequency carrier signal is varied proportionally by a lower-frequency modulating signal. The output contains the original carrier frequency plus upper a…
Definition
Why it is in scope
a signal processing technique where the amplitude of a carrier signal is varied by a modulating signal, producing sum and difference frequency components, used in communications, audio synthesis, and signal processing
Names and aliases
- amplitude-modulationen · CANONICAL
Relations from this entry
- cmsps9i0v06eejlssqrjcqyviINSTANCE_OF →
Amplitude modulation is a specific signal processing technique for varying carrier amplitude. Competent speaker test: amplitude modulation is a kind of signal processing. Specific→general, nearest kind.
- modulationINSTANCE_OF →
Amplitude-modulation is a specific kind of modulation technique: varying the amplitude of a carrier signal in proportion to a modulating signal. Nearest kind is modulation itself.
Relations to this entry
- ring-modulator← INSTANCE_OF
A ring modulator is a specific kind of amplitude modulation: specifically, double-sideband suppressed-carrier AM. Both multiply two signals to produce sum and difference frequencies. The ring modulator's distinguishing feature is carrier suppression, making it a narrower sense of amplitude modulation.
- tremolo← DEPENDS_ON
Tremolo modulates signal amplitude using a low-frequency oscillator (LFO). Remove amplitude-modulation as a mechanism — no way to vary amplitude in a periodic fashion — and tremolo cannot operate. This passes the Law 8 removal test. Pin sense: amplitude-modulation as the mechanism of varying signal level by a modulating waveform.
- ring-modulator← DERIVED_FROM
Ring modulation is a form of amplitude modulation where the carrier signal is suppressed and the input is multiplied by a carrier waveform. It is historically and structurally derived from amplitude modulation — specifically double-sideband suppressed-carrier (DSB-SC) modulation. The carrier frequency comes from an oscillator, and the modulation mathematically is AM without the carrier term.
- envelope-detection← DERIVED_FROM
Envelope detection was developed as the standard demodulation technique for AM signals. AM modulation predates and necessitates envelope detection — the technique exists because AM exists. Historical: AM radio development in early 1900s established both the modulation scheme and the envelope detector.
- tremolo← INSTANCE_OF
Tremolo is a specific kind of amplitude modulation: it varies the amplitude of a carrier (audio) signal using a modulating signal (LFO waveform), producing the characteristic pulsating effect. Competent speaker test: 'tremolo is a form of amplitude modulation' — yes. Nearest kind is amplitude-modulation, which is already an accepted entry with its own accepted definition.
Record identity
- Created
- Sep 6, 2026, 10:46 AM UTC
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- 59f15034ae8de99d77103790065b2f82d90c43a36b69e42ae0f042789d65de4f