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:
Dec. 14, 2004
Filed:
May. 01, 2003
Clay von Mueller, San Diego, CA (US);
Robert J. Mos, San Diego, CA (US);
Semtek Innovative Solutions, Inc., San Diego, CA (US);
Abstract
A method and apparatus for placing and later determining the distance between transitions from a first logical state to a second logical state stored on a medium, for example, a document. This determination is used to precisely characterize the information pattern in order to authenticate the information and the medium on which the information is stored. The invention uses a reader having a leading and trailing read apparatus, which allow information to be read simultaneously from two or more locations spaced a known distance apart. The distance between the center lines of each read apparatus is preferably an odd integer multiple of one half the distance between logical clock transitions. The distance between a first transition at the leading read apparatus and a next transition at the trailing read apparatus is used as a reference, hence given the term the “Reference Value”. The Reference Value is compared with the distance between the first transition and a second transition on the medium. Detection of deviations in spacing between transitions is unaffected by variations if the velocity of the medium with respect to the reader. Thus, the present invention is a method and apparatus for reading and writing conventional ISO 7816 data with additional precisely placed pulses that appear as noise to conventional reading apparatuses and as data to the described invention. In addition the present invention applies to a medium, which moves at an uncontrolled velocity relative to a read/write apparatus with which the data is read and written.