US 5,017,906 AGranted

Apparatus and method for combining analog detection signals to provide enhanced alarm integrity

AssigneeAritech Corporation

InventorMath M. J. Pantus

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Abstract

An apparatus and method for combining detection signals generated by intrusion detection systems to provide improved alarm integrity therefor. The apparatus and method have utility with mixed sensor technology and single sensor technology detection systems. In one embodiment, analog detection signals generated by system sensors are combined in an analog multiplier and the resulting decision signal is compared via a unipolar threshold comparator or a window comparator. In another embodiment, analog detection signals are amplitude limited prior to being combined in the analog multiplier. In a further embodiment, analog detection signals are subjected to average value processing such that the decision signal has a value equal to one-half of the sum of the sensor signals. In yet a further embodiment, analog dectection signals are amplitude limited prior to average value processing.

Claims9

Dependent claims

An apparatus for combining analog detection signals generated by single sensor technology and mixed sensor technology intrusion detection systems, comprising:

means for generating first and second analog detection signals;
means for combining said first and second analog detection signals to provide an alarm decision signal having an amplitude;
comparator means having at least one predetermined threshold for comparing said amplitude of said alarm decision signal to said at least one predetermined threshold, said comparator means being operative in response to said amplitude exceeding said at least one predetermined threshold to generate an output signal for triggering a system alarm;
signal limiting means coupled to said first and second analog detection signal generating means for limiting amplitudes of said first and second analog detection signals to a predetermined limit value;
and
wherein said combining means provides said alarm decision signal having said amplitude equal to the amplitude of said first analog detection signal multiplied by the amplitude of said second analog detection signal.

3 more elements

Dependencies are inferred from the claim text.