frequency hopping with amplitudes level control -use a keyless anti - theft - remote control access system

摘要

A method for the blocking of an attack by two thieves on a passive strength - system is disclosed by the use of frequency hopping. Radio-frequency signals are between a trailer and a vehicle. The transmitted signals jumping between at least two high frequency end channels in a specific pseudo random pattern, which the vehicle is known. In the case of the vehicle the transmitted signals are received in a method, which is set sequentially, in order to the known characteristics of each part of the known pattern to be taken into account. Anomalies in the pattern of received signals are detected and an access to the vehicle is blocked when the anomalies permissible limit values are exceeded.