Radio transmission based alarm system for warning e.g. lorry drivers traveling on roadway about presence of e.g. mobile and/or fixed singular point, has generation unit modulated based on measurement function of level of received signal

摘要

The system has a transmitting beacon (2) for transmitting a radio operator signal (12) and placed at a singular point. A set of receivers (3) is available to motorists. Each receiver receives the signal and generates sound alarms when a level of received signal is higher than a determined threshold of an early alarm. The receiver comprises a measurement unit for measuring the level of the signal and a generation unit for generating an alarm. The generation unit is modulated according to the function of measurements of the level of the received signal to modify alarms according to the level.