Amplitude
physical quantity; (of a periodic variable) measure of its change over a single period (such as time or spatial period)
The amplitude of a periodic variable is a measure of its change in a single period (such as time or spatial period). The amplitude of a non-periodic signal is its magnitude compared with a reference value. There are various definitions of amplitude (see below), which are all functions of the magnitude of the differences between the variable's extreme values. In older texts, the phase of a periodic function is sometimes called the amplitude.
Definitions
Peak amplitude
In audio system measurements, telecommunications and others where the measurand is a signal that swings above and below a reference value but is not sinusoidal, peak amplitude is often used. If the reference is zero, this is the maximum absolute value of the signal; if the reference is a mean value (DC component), the peak amplitude is the maximum absolute value of the difference from that reference.
Peak-to-peak amplitude
Peak-to-peak amplitude (abbreviated p–p or PtP or PtoP) is the change between peak (highest signal value) and trough (lowest signal value, which can be negative). With appropriate circuitry, peak-to-peak amplitudes of electric oscillations can be measured by meters or by viewing the waveform on an oscilloscope. Peak-to-peak is a straightforward measurement on an oscilloscope, the peaks of the waveform being easily identified and measured against the graticule. This remains a common way of specifying amplitude, but sometimes other measures of amplitude are more appropriate.
The public source identifies “Amplitude” as physical quantity; (of a periodic variable) measure of its change over a single period (such as time or spatial period). This brief keeps that definition visible, then builds a research path around Amplitude, physical and quantity.
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Vocabulary and entity names are the principal evidence signals here, because they determine the precision of every later search. The source revision retrieved here is dated Sep 6, 2026. The linked authority identifier is Q159190. None of the 0 selected statements returned an explicit reference.
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This entry incorporates text from “Amplitude” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.