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.

Date of Patent:
Apr. 25, 2000

Filed:

Aug. 24, 1998
Applicant:
Inventors:

David Edwin Proctor, Gauteng, ZA;

Christopher Gordon Turner, Gauteng, ZA;

Assignee:
Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
G08B / ;
U.S. Cl.
CPC ...
3405727 ; 3405721 ; 3406931 ; 342 27 ; 342 44 ; 342 51 ;
Abstract

A transponder 20 for an electronic identification system transponder is characterized in that it presents a high input impedance (>400.OMEGA.) at an input thereof which is directly connected to an antenna 22 with a matched high input impedance. The transponder is aimed at improving the voltage recovered on capacitor C.sub.2 from an interrogation signal and thus the operational range of the system. The modulator 30 of the transponder is arranged to backscatter modulate the interrogation signal at a modulation depth of less than 80%, preferably in the order of 30%. This also results in an improvement of the operational range of the system.


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