Passband bandwidth of radio channel

The difference between the upper and lower cutoff frequencies of radio communication channel.

Path loss

Decrease in signal strength that occurs when an electromagnetic wave travels over a radio path.

Peak envelope power

The average power supplied to the antenna transmission line by a transmitter during one radio frequency cycle at the crest of the modulation envelope, under normal operating conditions.



Permissible interference

Observed or predicted interference which complies with quantitative interference and sharing criteria contained in Radio Regulations or in ITU-R Recommendations or in special agreements as provided for in Radio Regulations.

Point-to-area communication

Communication provided by links between a station located at a specified fixed point and any number of stations located at non-specified points in a given area which is the coverage area of this station.

Point-to-multipoint communication

Communication provided by links, for example, radio-relay links between a single station located at a specified fixed point and a number of stations located at specified fixed points.

Point-to-point communication

Communication provided by a link, for example, a radio-relay link between two stations located at specified fixed points.


Process or phenomenon in which the waves of light or other electromagnetic radiation are restricted to certain directions of vibration, usually specified in terms of the electric field vector.

Polarisation of radio wave

Orientation of the electric vector onto fixed plane in space, which plane is perpendicular to the direction of propagation.

Power density

The amount of power (time rate of energy transfer) per unit volume (or unit area).

Power flux density

A measure of the energy that flows through a unit area each unit time (second). The unit of time may be expressed in the unit of frequency instead (Hertz).

Power gain relative to a dipole

Parameter, which is the ratio of the power received / transmitted by the antenna to the power that would be received / transmitted by a half-wave dipole antenna.

Power gain relative to an isotropic radiator

Parameter, which is the ratio of the power received / transmitted by the antenna to the power that would be received / transmitted by a hypothetical isotropic antenna.

Power spectral density

A positive real function of a frequency variable associated with a stationary stochastic process, or a deterministic function of time. It describes how the power of a signal is distributed with frequency.


PSD, usually measured in W/Hz

Preferential frequency

Frequency which the Administrations concerned may assign, without prior coordination, on the basis of bi- or multilateral agreements under the terms laid down therein.

Process engineering

1) Method for the production or manufacturing process. 2) Field of technology dealing with the development of new methods of production or processing of raw materials.

Propagation model

1) Formal notation characterizing the propagation of radio waves. 2) A set of empirical (mathematical) formulas for the characterization of radio wave propagation as a function of frequency, distance and other specified conditions.

Propagation path

1) A path from one point to another, over which the electromagnetic wave travels. 2) The great-circle distance between the transmitter and receiver antenna sites.

Protection ratio

The minimum value of the wanted-to-unwanted signal ratio, usually expressed in decibels, at the receiver input, determined under specified conditions such that a specified reception quality of the wanted signal is achieved at the receiver output.