Crest factor (original) (raw)

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峰值因數（crest factor，又稱peak-to-average ratio，簡稱PAR）是和波形有關的無因次量，為波形的振幅再除以波形RMS （time-averaged）所得到的值。 峰均功率比（peak-to-average power ratio，簡稱PAPR）是另一個相關的無因次量，定義為振幅平方（表示峰值功率）除以RMS平方（表示平均功率）的比值： 因一波形的振幅恆大於等於RMS值，因此峰值因數及峰均功率比的最小值均為1。

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dbo:abstract Der Scheitelfaktor oder Crestfaktor (englisch crest factor) beschreibt in der Elektrotechnik das Verhältnis von Scheitelwert zu Effektivwert einer Wechselgröße und ist immer größer oder gleich eins. Anwendung findet er in Bereichen der elektrischen Messtechnik, Nachrichtentechnik, Tontechnik und Akustik. Er dient wie der Formfaktor oder der Klirrfaktor als Kennwert zur groben Beschreibung der Kurvenform einer Wechselgröße. Das Quadrat des Scheitelfaktors wird als englisch Peak-to-average power ratio (PAPR) bezeichnet und drückt das Verhältnis von Spitzenleistung zu der mittleren Leistung eines Signals aus. Der PAPR wird üblicherweise als logarithmisches Maß in Dezibel angegeben. Er dient unter anderem bei Funkempfängern zur Gewinnung eines Steuersignals zur automatischen Verstärkungsregelung (AGC). (de) Crest factor is a parameter of a waveform, such as alternating current or sound, showing the ratio of peak values to the effective value. In other words, crest factor indicates how extreme the peaks are in a waveform. Crest factor 1 indicates no peaks, such as direct current or a square wave. Higher crest factors indicate peaks, for example sound waves tend to have high crest factors. Crest factor is the peak amplitude of the waveform divided by the RMS value of the waveform. The peak-to-average power ratio (PAPR) is the peak amplitude squared (giving the peak power) divided by the RMS value squared (giving the average power). It is the square of the crest factor. When expressed in decibels, crest factor and PAPR are equivalent, due to the way decibels are calculated for power ratios vs amplitude ratios. Crest factor and PAPR are therefore dimensionless quantities. While the crest factor is defined as a positive real number, in commercial products it is also commonly stated as the ratio of two whole numbers, e.g., 2:1. The PAPR is most used in signal processing applications. As it is a power ratio, it is normally expressed in decibels (dB). The crest factor of the test signal is a fairly important issue in loudspeaker testing standards; in this context it is usually expressed in dB. The minimum possible crest factor is 1, 1:1 or 0 dB. (en) Le facteur de crête est une mesure caractéristique d'un signal. C'est le rapport entre l'amplitude du pic du signal et la valeur efficace du signal. Il est couramment corrélé avec le PAPR (Peak-to-Average Power Ratio) qui indique un rapport entre puissance crête et puissance moyenne : C'est donc une valeur sans dimension. La plupart du temps, cette grandeur est exprimée à l'aide d'un nombre décimal positif, mais pour les produits commerciaux, on donne souvent un ratio de deux chiffres (2:1 par exemple). En traitement du signal, il est souvent exprimé en decibels (dB). La plus petite valeur possible est 1, que l'on peut aussi écrire 1:1 ou encore 0 dB. (fr) Il Fattore di cresta è una misura di una forma d'onda indicativa del rapporto tra i valori di picco e il suo valore efficace. Essendo calcolato come un rapporto: un valore pari a 1 indica che non sono presenti picchi, come per la corrente continua, mentre un valore alto è indicativo della presenza di picchi nel segnale, come ad esempio per le onde sonore, le quali tendono ad avere fattori di cresta elevati. Il fattore di cresta è calcolato come il valore di picco dell'ampiezza diviso il valore efficace (RMS) della forma d'onda: Il peak-to-average power ratio (PAPR) è il picco dell'ampiezza al quadrato (potenza di picco) diviso per l'RMS al quadrato (potenza media). Esso risulta quindi essere il quadrato del fattore di cresta: Quando espresso in decibel, il fattore di cresta e il PAPR sono equivalenti. (it) 峰值因數（crest factor，又稱peak-to-average ratio，簡稱PAR）是和波形有關的無因次量，為波形的振幅再除以波形RMS （time-averaged）所得到的值。 峰均功率比（peak-to-average power ratio，簡稱PAPR）是另一個相關的無因次量，定義為振幅平方（表示峰值功率）除以RMS平方（表示平均功率）的比值： 因一波形的振幅恆大於等於RMS值，因此峰值因數及峰均功率比的最小值均為1。 (zh)
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rdfs:comment 峰值因數（crest factor，又稱peak-to-average ratio，簡稱PAR）是和波形有關的無因次量，為波形的振幅再除以波形RMS （time-averaged）所得到的值。 峰均功率比（peak-to-average power ratio，簡稱PAPR）是另一個相關的無因次量，定義為振幅平方（表示峰值功率）除以RMS平方（表示平均功率）的比值： 因一波形的振幅恆大於等於RMS值，因此峰值因數及峰均功率比的最小值均為1。 (zh) Crest factor is a parameter of a waveform, such as alternating current or sound, showing the ratio of peak values to the effective value. In other words, crest factor indicates how extreme the peaks are in a waveform. Crest factor 1 indicates no peaks, such as direct current or a square wave. Higher crest factors indicate peaks, for example sound waves tend to have high crest factors. Crest factor is the peak amplitude of the waveform divided by the RMS value of the waveform. The minimum possible crest factor is 1, 1:1 or 0 dB. (en) Der Scheitelfaktor oder Crestfaktor (englisch crest factor) beschreibt in der Elektrotechnik das Verhältnis von Scheitelwert zu Effektivwert einer Wechselgröße und ist immer größer oder gleich eins. Anwendung findet er in Bereichen der elektrischen Messtechnik, Nachrichtentechnik, Tontechnik und Akustik. Er dient wie der Formfaktor oder der Klirrfaktor als Kennwert zur groben Beschreibung der Kurvenform einer Wechselgröße. (de) Le facteur de crête est une mesure caractéristique d'un signal. C'est le rapport entre l'amplitude du pic du signal et la valeur efficace du signal. Il est couramment corrélé avec le PAPR (Peak-to-Average Power Ratio) qui indique un rapport entre puissance crête et puissance moyenne : C'est donc une valeur sans dimension. La plupart du temps, cette grandeur est exprimée à l'aide d'un nombre décimal positif, mais pour les produits commerciaux, on donne souvent un ratio de deux chiffres (2:1 par exemple). En traitement du signal, il est souvent exprimé en decibels (dB). (fr) Il Fattore di cresta è una misura di una forma d'onda indicativa del rapporto tra i valori di picco e il suo valore efficace. Essendo calcolato come un rapporto: un valore pari a 1 indica che non sono presenti picchi, come per la corrente continua, mentre un valore alto è indicativo della presenza di picchi nel segnale, come ad esempio per le onde sonore, le quali tendono ad avere fattori di cresta elevati. Il fattore di cresta è calcolato come il valore di picco dell'ampiezza diviso il valore efficace (RMS) della forma d'onda: (it)
rdfs:label Činitel výkyvu (cs) Scheitelfaktor (de) Crest factor (en) Facteur de crête (fr) Fattore di cresta (it) 峰值因數 (zh)
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