Multichannel anti-intruder surveillance system - has ultrasonic surveillance device coupled to supply via switch controlled by hyperfrequency device

摘要

The surveillance system uses at least two surveillance devices, each covering the whole of the surveillance zone or all the possible exits for the latter, the two devices monitoring different physical parameters. The surveillance devices are coupled to a coincidence circuit (18) for activating the alarm only if all the devices are activated for a short time period. One of the surveillance devices is coupled to the supply via a switch (30) controlled by a further device. The first surveillance device is only connected to the supply when the second surveillance device is energised. Pref. the surveillance system uses ultrasonic (2, 4, 6, 8) and hyperfrequency (10, 12, 14, 16) surveillance devices.