power: 1. The rate of transfer or absorption of energy per unit time in a system. (188) 2. Whenever the power of a radio transmitter etc. is referred to, it shall be expressed in one of the following forms, according to the class of emission, using the arbitrary symbols indicated:

For different classes of emission, the relationships between peak envelope power, mean power and carrier power, under the conditions of normal operation and of no modulation, are contained in CCIR Recommendations which may be used as a guide. For use in formulae, the symbol p denotes power expressed in watts and the symbol P denotes power expressed in decibels relative to a reference level. [NTIA] [RR]
