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US 5,517,175 AGranted
Potential adjusting sensor supervision circuit
AssigneeStellar Security Products, Inc.
InventorsGlenn A. Brown, Robert B. Weinhold
Life of this patent
Estimating the term…
Abstract
A warning or alarm sensor supervision circuit employs varying voltage levels which may vary at random intervals and to random levels.
Claims8
In a microprocessor based security system, having a control unit including the microprocessor, and at least one supervision circuit including at least one alarm sensor, an arrangement comprising:
- first means for providing a reference voltage signal to the at least one supervision circuit;
- second means for receiving the reference voltage signal from the first means, for receiving an input voltage signal from the at least one supervision circuit, and for producing a voltage sample signal, the input voltage signal and the voltage sample signal being dependent on the reference voltage signal and being dependent on the state of the at least one supervision circuit;
- and
- evaluating means for analyzing and classifying the voltage sample signal into one of ALARM, TAMPER and SECURE categories based on predetermined criteria;
- wherein said first means includes voltage variation means for varying the reference voltage signal under the control of the control unit.
2 more elements
In a microprocessor based security system, having a control unit including the microprocessor, at least one supervision circuit including at least one alarm sensor, and an analog to digital converter, a method comprising:
- providing a reference voltage signal to the at least one supervision circuit, the reference voltage signal being varied under the control of the control unit;
- receiving the reference voltage signal, receiving an input voltage signal from the at least one supervision circuit, and producing a voltage sample signal, with the analog to digital converter, the input voltage signal and the voltage sample signal being dependent on the reference voltage signal and being dependent on the state of the at least one supervision circuit;
- and
- analyzing and classifying the voltage sample signal into one of ALARM, TAMPER and SECURE categories based on predetermined criteria.
1 more element
Dependencies are inferred from the claim text.