Description: ten times the logarithm to the base 10 of the ratio of the sound power radiated by a sound source to the reference sound power (P0 = 10?12 W); Name: acoustic power level
Description: ten times the logarithm to the base 10 of the ratio of the sound power of a source, p, to a reference value, p0, expressed in decibels; Name: sound output level
Description: Probability that an item is in a state to perform as required at a given instant, under given conditions, assuming that the necessary external resources are provided ; Name: Instantaneous availability