FIELD: radio engineering, communication.
SUBSTANCE: disclosed is a method of detecting intrusion of a short-wave radio signal into a power line data transmission system, comprising steps of determining the level of the in-phase signal at the frequency of the power line data transmission system over a period of time when there is no data transmission in the power line data transmission system at said frequency, and detecting intrusion if the level of the in-phase signal is higher than a threshold value. A corresponding power line data transmission modem is also provided.
EFFECT: high reliability.
11 cl, 5 dwg
