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SNET: U S Patent: Identification system
From: [email protected] (Jeremy Compton)
Subject: SNET: U S Patent: Identification system
Date: Thu, 17 Sep 1998 01:35:51 +1200
To: [email protected]
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United States Patent
5,041,826
Milheiser
Aug. 20, 1991
Identification system
Abstract
A passive integrated transponder (PIT) is attached to or embedded in an
item to be identified. It is excited via an inductive coupling from an
interrogator. The PIT responds to the interrogator via the inductive
coupling with a signal constituting a
stream of data unique to the identified item. The signal is in the form of
two different frequencies, a shift from one frequency to the second during
a bit cell representing a data "one", and a shift from the second frequency
to the first frequency representing a data "zero". The responsive signal is
then detected and processed for utilization in a data storage or display
device.
Inventors:
Milheiser; Thomas A. (Littleton, CO).
Assignee:
Destron/IDI Inc. (Boulder, CO).
Appl. No.:
481,833
Filed:
Feb. 16, 1990
Related U.S. Application Data
Division of Ser No. 388,761, Aug. 2, 1989, abandoned, which is a
continuation of Ser. No. 165,310, Mar. 8,
1988, abandoned, which is a division of Ser. No 814,492, Dec. 30, 1985,
Pat. No. 4,730,188, which is a
continuation-in-part of Ser. No. 580,401, Feb. 15, 1984, abandoned.
Intl. Cl. :
H04Q 1/00
Current U.S. Cl.:
340/825.54;
340/825.69; 375/272; 455/41
Field of Search:
340/825.54, 825.55,
825.69, 825.72, 825.34, 825.94, 572;
455/118, 41;
375/45, 62, 78, 81, 52; 370/53, 112
References Cited | [Referenced By]
U.S. Patent Documents
3,109,143
Oct., 1963
Gluth
375/81
3,510,779
May, 1970
Klapper
375/81
3,689,885
Sept., 1972
Kaplan et al.
455/41 X
4,287,596
Sept., 1981
Chari
375/52 X
4,313,033
Jan., 1982
Walker et al.
370/112 X
4,368,439
Jan., 1983
Shibuya et al.
375/62 X
4,388,730
Jun., 1983
Nash et al.
375/81 X
Primary Examiner: Weldon; Ulysses
Attorney, Agent or Firm: Sirr; Francis A., Hancock; Earl C.
14 Claims, 8 Drawing Figures
[USPTO]
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-> Posted by: [email protected] (Jeremy Compton)