ATPC: (Automatic Transmit Power Control) An electronic process for controlling the radio frequency transmission power at the transmitting site in dependence upon the received power level at the opposite site. This ensures that an increased transmission power or the maximum value of this power is only transmitted at times when the conditions for the microwave propagation can lead to problems. Otherwise, for 80 % of the time, the radio frequency power of the transmitter is reduced to a fraction of this value.

The received signal level, however, is a composite signal that in addition to the useful signal can be overlaid by various noise and interference signals. Consequently, intelligent ATPC mechanisms combine the measured receiving power with a bit error analysis and on the basis of both items of information control the opposing transmitter.