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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). [1] 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.
Peak envelope power (PEP) is the average power over a single radio frequency cycle at the crest of the modulation. This is a Federal Communications Commission definition. PEP is normally considered the occasional or continuously repeating crest of the modulation envelope under normal operating conditions.
The power spectral density (PSD) of the signal describes the power present in the signal as a function of frequency, per unit frequency. Power spectral density is commonly expressed in SI units of watts per hertz (abbreviated as W/Hz). [2]
Hence, the contribution to the average power of () coming from the component with frequency is . All these contributions add up to the average power of x ( t ) . {\displaystyle x(t).} Then the power as a function of frequency is 1 2 A k 2 , {\displaystyle {\tfrac {1}{2}}A_{k}^{2},} and its statistical cumulative distribution function S ( ν ...
The 41.8% point is the wavelength-frequency-neutral peak (i.e. the peak in power per unit change in logarithm of wavelength or frequency). These are the points at which the respective Planck-law functions 1 / λ 5 , ν 3 and ν 2 / λ 2 , respectively, divided by exp ( hν / k B T ) − 1 attain their maxima.
Peak values can be calculated from RMS values from the above formula, which implies V P = V RMS × √ 2, assuming the source is a pure sine wave. Thus the peak value of the mains voltage in the USA is about 120 × √ 2, or about 170 volts. The peak-to-peak voltage, being double this, is about 340 volts.
[16] [1] [17] [18] For other waveforms, the relationship between peak power and average power is the peak-to-average power ratio (PAPR). The peak power of an amplifier is determined by the voltage rails and the maximum amount of current its electronic components can handle for an instant without damage.
Intensity is used most frequently with waves such as acoustic waves , matter waves such as electrons in electron microscopes, and electromagnetic waves such as light or radio waves, in which case the average power transfer over one period of the wave is used. Intensity can be applied to other circumstances where energy is transferred.