| 摘要 |
PCT No. PCT/EP95/01331 Sec. 371 Date Mar. 13, 1997 Sec. 102(e) Date Mar. 13, 1997 PCT Filed Apr. 11, 1995 PCT Pub. No. WO95/28692 PCT Pub. Date Oct. 26, 1995A combined technology event detection device for detection of an event such as movement and/or body temperature, such as an intrusion detection device. The event detection device includes: a passive infrared (PIR) sensor to generate a first output signal in response to detection of an event; a microwave sensor to generate a second output signal in response to detection of an event; a logic device to receive the first and second output signals, which activates an alarm in response thereto; and a fault monitoring system. The fault monitoring system includes: a first counter to store the number of first output signals received from the PIR sensor; a second counter to store the number of second output signals received from the microwave sensor; a signal detector to detect an output signal from either the PIR sensor or the microwave sensor, increment the counter associated with the sensor generating the output signal in response thereto, and re-set the counter not associated with the sensor generating the output signal to a base level; and a logic device which generates an output signal indicative of a fault condition in the event detection device when the number of output signals stored in a counter exceeds a predetermined threshold. |
