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:
Jun. 11, 1991
Filed:
Jan. 02, 1990
Applicant:
Inventors:
Kenneth C Zemlok, Shelton, CT (US);
Andrei Obrea, Bethel, CT (US);
Assignee:
Pitney Bowes Inc., Stamford, CT (US);
Primary Examiner:
Int. Cl.
CPC ...
G08B / ;
U.S. Cl.
CPC ...
340572 ;
Abstract
A frequency-swept electromagnetic field is generated in an interrogation zone and signals received from the interrogation zone are processed to detect the presence of a marker with a resonant tank circuit in the zone. Detection is achieved by the use of averaging techniques of a plurality of sweeps wherein peaks above a defined level are stored in a persistence table. A symmetry test is made on the peaks and if the peaks are persistence and symmetrical the presence of a marker is indicated since background noise will not exhibit persistence and symmetry.