System and method for dynamic adjustment of filtering in an alarm system
First Claim
1. A method of processing a signal from an ambient condition detector wherein a selected profile, when present, is indicative of the presence of a predetermined condition;
- the method comprising;
smoothing the signal to a selected degree, so as to minimize noise not correlated with the profile, thereby producing a smoothed signal; and
detecting in the signal the presence of the selected profile, and, in response thereto decreasing the degree of smoothing.
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Abstract
A system and a method for dynamically adjusting a level of filtering or smoothing applied to data received from fire detectors produces shortened response times for detection of a fire condition while at the same time minimizing the effects of uncorrelated noise in the absence of any fire condition. An increasing probability of a fire results in less filtering. Increasing values of the input signal from a respective detector, indicative of an increasing selected ambient condition such as combustion or temperature, provide a control input for reducing or bypassing the level of filtering of the respective input signal thereby reducing system response time. Where the unfiltered input data from a respective detector indicates a combustion or temperature profile moving toward clear air, the filtering or smoothing level can also be dynamically decreased thereby enabling the filtered signal values to return to their respective clear air values faster than would otherwise be the case. Detectors can be grouped and multiple unfiltered outputs can be assessed substantially simultaneously to determine whether or not levels of filtering or smoothing for the members of the group should be dynamically decreased.
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Citations
38 Claims
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1. A method of processing a signal from an ambient condition detector wherein a selected profile, when present, is indicative of the presence of a predetermined condition;
- the method comprising;
smoothing the signal to a selected degree, so as to minimize noise not correlated with the profile, thereby producing a smoothed signal; and detecting in the signal the presence of the selected profile, and, in response thereto decreasing the degree of smoothing. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
- the method comprising;
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12. A method of processing a signal from an ambient condition sensor wherein a selected signal profile, when present, is indicative of the potential presence of a fire, the method comprising:
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filtering the signal to a selected degree so as to minimize noise not correlated with the profile, thereby producing a filtered signal; and detecting in the signal the presence of at least one parameter potentially indicative of the presence of a fire and in response to a detected presence, altering the degree of filtering a predetermined amount; and processing the filtered signal to detect the presence of an alarm condition. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method of processing signals from a plurality of ambient condition detectors wherein the signals are each indicative of an ambient condition in the vicinity of a respective detector, the method comprising:
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filtering each of the signals from the detectors in a selected group, which includes at least two detectors, thereby producing a plurality of filtered signals; and determining for each signal if a predetermined profile is present, and, in response to a detected profile, reducing a degree of filtering associated with at least some members of the group. - View Dependent Claims (23, 24, 25, 26)
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27. An ambient condition detecting system comprising:
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a control unit; a communications link coupled to the control unit; a plurality of ambient condition detectors coupled to the link wherein the detectors provide electrical signals, indicative of adjacent ambient conditions, to the control unit via the link, wherein the control unit includes circuitry for filtering to a selected degree at least one of the electrical signals, to reduce uncorrelated noise thereby producing a respective filtered signal, and wherein the control unit includes further circuitry to detect the presence of a predetermined profile in the one signal, and in response thereto, to dynamically alter the degree of filtering. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36)
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37. An ambient condition detecting system comprising:
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at least one ambient condition sensor; a processor for receiving an electrical signal from the sensor wherein the processor includes circuitry for filtering the signal to a selected degree and circuitry for determining if the signal exhibits a predetermined profile, and in response thereto reducing the degree of filtering. - View Dependent Claims (38)
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Specification