The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 04, 2000
Filed:
Sep. 26, 1997
James Stoffer, Delafield, WI (US);
Innovative Control Systems, Waukesha, WI (US);
Abstract
A system for monitoring a person in a secured zone is disclosed. One or more transmitters transmit a first signal into the zone. The person wears a tag that receives the first signal. The tag transmits a second signal that is responsive to the first signal. A receiver receives the second signal and provides a third signal responsive to the first signal. A controller is connected to the receiver and includes a discrimination circuit that determines if the third signal is responsive to the first signal. The controller provides an alarm signal if responsiveness is found. The responsiveness may be a constant phase relationship, and data may be transmitted by the tag at a frequency derived from the first frequency. A three loop antenna, with each loop disposed in a unique plane is described. Each unique plane is substantially perpendicular to the other unique planes, in another embodiment. The tag includes a band removal circuit that senses the skin resistivity of the patient in another embodiment. The tag may also include a chest band that senses the respiration of the patient. The tag includes a power circuit that reduces power consumption in the event the second signal is not being transmitted.