In most circuits for wireless applications, it is necessary to monitor and control both the transmitted and received levels of silicon aluminum -RF power. This is done to minimize power amplifier (PA) current consumption, control receiver gain, optimize performance and efficiency, and meet signal-strength regulatory mandates.
To measure RF power, three different approaches are used: the peak detector/amplifier, the logarithmic (log) amplifier, and the RMS converter. Each of these meets the application priorities and needs of the different types of complex RF waveforms, as well as the performance and cost issues.
Note that RF power measurement can be done in two venues: wireless and wired. For wireless, the actual radiated power is sensed by a transducer such as a diode target, which then produces a signal proportional to the RF power which impinges on it. This is a true "RF power" measurement.
Also note that some RF power-measurement subsystems use the term "video" instead of "RF". This is a holdover from the past, when wideband signals where primarily used for video applications. The video adjective is still used in some legacy products and literature.