| 摘要 |
<p>A multisensor intrusion detection system having greatly improved immunity to false alarms employs a first sensor (66) for sensing an intrusion in a volume of space by a first physical phenomenon and a second sensor (500) for detecting an intrusion in the volume of space by a second physical phenomenon different from the first physical phenomenon. The first sensor (66) generates a first signal in response to the detection of an intrusion into the volume of space, and the second sensor generates a second signal in response to a detection of an intrusion. A microcontroller (12) generates an alarm signal upon the occurrence of one first signal and one second signal within a first interval, the occurrence of another first signal within a subsequent second interval and the occurrence of another second signal within a third subsequent interval. The microcontroller (12) waits (A) in state O until one first signal and one second signal occur within the first interval, whereupon its state changes (B) to state 1 from which it returns (C) to state O unless another first signal occurs within the subsequent second interval, whereupon it changes (D) to state 2 from which it returns (E) to state O unless there is an occurrence of another second signal within the third subsequent interval, whereupon it changes to the ALARM state. It returns (G) to state O from the ALARM state after a predetermined fourth interval. <IMAGE></p> |
