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:
Nov. 05, 2002
Filed:
Mar. 06, 2001
Donald K. Belcher, Rogersville, TN (US);
John A. Eisenberg, Los Altos, CA (US);
Ronald J. Hash, Rogersville, TN (US);
Douglas C. Bowman, Capitola, CA (US);
Wherenet Corp., Santa Clara, CA (US);
Abstract
The unwanted influence a noise-source environment upon a modulated (e.g., FSK-encoded) magnetic field-based communication system is diminished by a non-modulated AC magnetic field communication scheme that uses a demodulatorless magnetic field detector. When installed in a tag to be tracked by a geolocation system, the demodulatorless detector responds when the tag comes within a prescribed proximity of the field generator producing the non-modulated AC magnetic field. The received signal is downconverted to baseband and processed to detect a valid AC magnetic field tone and indicate whether the tag is within a prescribed proximity of the AC magnetic field source.