초록 ▼

An alarm system has two output modes, one providing relatively high detection probability and the other providing relatively low false alarm probability. Two or more sensors are coupled to an associated logic circuit which provides a first alarm output in response to actuation of any one of the sens

An alarm system has two output modes, one providing relatively high detection probability and the other providing relatively low false alarm probability. Two or more sensors are coupled to an associated logic circuit which provides a first alarm output in response to actuation of any one of the sensors, and a second alarm output in response to actuation of the two or more sensors within a predetermined time interval.

대표청구항 ▼

An alarm system comprising: a plurality of sensors providing overlapping coverage of a common protected area and each providing a sensor signal when actuated by an alarm condition in the protected area; OR circuit means coupled to said sensors and operative in response to any one of the sensor signa

An alarm system comprising: a plurality of sensors providing overlapping coverage of a common protected area and each providing a sensor signal when actuated by an alarm condition in the protected area; OR circuit means coupled to said sensors and operative in response to any one of the sensor signals to provide a first alarm signal having high detection reliability; and logic circuit means coupled to said sensors and operative in response to sensor signals from at least two of said sensors present within a predetermined time interval to provide a second alarm signal having a low false alarm rate; said time interval commencing immediately upon the occurrence of the first of said sensor signals.