Detection system and method for determining an alarm condition therein
First Claim
Patent Images
1. A method for determining an alarm condition for a confined space, the method characterised by the steps of:
- detecting low frequency acoustic signals in the confined space by a secondary microphone sensor;
generating an alarm signal by the secondary microphone sensor in response to detected low frequency acoustic signals;
determining whether the alarm signal represents a false alarm condition by filtering the detected alarm signal into one of two or more frequency bands to discriminate between various types of signal-source, such that a low frequency of the two or more frequency bands represents an alarm signal from the secondary microphone sensor, and a high frequency of the two or more frequency bands represents an alarm signal from a primary alarm sensor; and
de-sensitizing the primary alarm sensor in response to the determined false alarm condition at the high frequency band.
1 Assignment
0 Petitions
Accused Products
Abstract
A method (300) for determining an alarm condition for a confined space comprises detecting motion or an intrusion (305) in the confined space by a secondary sensor and generating (310) an alarm signal by the secondary sensor in response to detected motion or an intrusion. The method further comprises the steps of determining (315) whether the alarm signal represents a false alarm condition; and inhibiting (325) a primary sensor in response to a determined false alarm condition. The provision of a secondary sensor is used to identify false alarms and inhibit operation of the primary sensor or alarm in response thereto.
-
Citations
13 Claims
-
1. A method for determining an alarm condition for a confined space, the method characterised by the steps of:
-
detecting low frequency acoustic signals in the confined space by a secondary microphone sensor; generating an alarm signal by the secondary microphone sensor in response to detected low frequency acoustic signals; determining whether the alarm signal represents a false alarm condition by filtering the detected alarm signal into one of two or more frequency bands to discriminate between various types of signal-source, such that a low frequency of the two or more frequency bands represents an alarm signal from the secondary microphone sensor, and a high frequency of the two or more frequency bands represents an alarm signal from a primary alarm sensor; and de-sensitizing the primary alarm sensor in response to the determined false alarm condition at the high frequency band. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. A detection system for determining an alarm condition within a confined space comprising a primary alarm sensor, the detection system characterised by:
-
a secondary alarm microphone sensor arranged to generate an alarm signal in response to detected low frequency acoustic signals in the confined space; and a signal processor operably coupled to the primary alarm sensor and secondary alarm microphone sensor, and configured to determine whether the alarm signal represents a false alarm condition by discriminating between various types of signal sources, and a filter operably coupled to the signal processor and arranged to discriminate between various types of signal source by filtering alarm signals having different frequency responses into two or more frequency bands, wherein the signal processor interprets an alarm signal filtered at a low frequency as representing an alarm signal from the secondary sensor, and a signal filtered at a high frequency as representing an alarm signal from the primary alarm sensor and performs a de-sensitize operation of the primary alarm sensor in response to the determined false alarm condition at the high frequency band. - View Dependent Claims (9, 10, 11, 12, 13)
-
Specification