Multizone intrusion alarm system
AssigneeAmerican District Telegraph Company
InventorsAaron A. Galvin, L. Dennis Shapiro
Life of this patent
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Abstract
An intrusion alarm system for use with a plurality of protected zones and providing an output indication of a particular zone or zones in which intrusion has occurred. A lesser number of signal processors are employed than the number of zones being protected. Signals received from each protected zone are selectively combined to provide different summed signals which are applied to respective processors that are shared by the zones and the output signals of which are processed by logic circuitry to provide an output indication of the presence of an intruder and an indication of the zone in which intrusion has occurred.
Claims6
A multiple zone intrusion alarm system comprising:
- a plurality of transmitting and receiving means each disposed in a respective zone under protection and each including means for propagating a signal in said zone and means for receiving signals returned from said zone and from objects therein;
- means for selectively combining said returned signals to provide a plurality of differently combined signal versions thereof, said signal versions being less in number than the number of zones being protected;
- a plurality of signal processors of a lesser number than the number of zones under protection and each operative to discriminate between an actual intruder and spurious signal conditions, each signal processor receiving a respective one of said signal versions and providing an output signal in response thereto;
- and
- decoder means operative in response to said output signals from said signal processors to provide a plurality of signals each corresponding to a respective protected zone and each representative of intruder presence in said zone.
For use in an intrusion alarm system having in each of a plurality of protected zones means for receiving signals from said zone and from objects therein, said signals containing information representative of intruder presence in said zone, circuitry for providing an output indication of a zone in which intrusion occurs, said circuitry comprising:
- means for selectively combining said returned signals to provide a plurality of differently combined signal versions thereof, said signal versions being less in number than the number of said protected zones;
- a plurality of signal processors equal in number to the number of said signal versions and each operative to discriminate between an actual intruder and spurious signal conditions, each signal processor receiving a respective one of said signal versions and providing an output signal in response thereto;
- and
- decoder means operative in response to said output signals from said signal processors to provide a plurality of signals each corresponding to a respective one of said protected zones and each representative of intruder presence in said zone.
Dependencies are inferred from the claim text.