Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
2006-04-25
2006-04-25
Hofsass, Jeffery (Department: 2636)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S567000
Reexamination Certificate
active
07034687
ABSTRACT:
An anti-theft surveillance system capable of detecting the presence of tags affixed to merchandise. The tags contain a diode attached to two dipole elements. When the tag receives alow frequency signal and a high frequency signal, it will emit two side bands. The system includes alow frequency transmitter, a high frequency transmitter, and a receiver. The two transmitters place alow frequency signal and a high frequency signal in proximity to the guarded area (typically a store doorway). When a tag is near the doorway, the receiver will receive the upper side band and lower side band. The receiver reduces the frequency of the upper and lower side band signals to form an intermediate frequency upper side band and an intermediate frequency lower side band. These two intermediate frequency signals are then fed into two separate detector circuits. One circuit detects the presence of the intermediate frequency upper side band and the other circuit detects the presence of the intermediate frequency lower side band. Only if both side bands are detected is an alarm created.
REFERENCES:
patent: 2774060 (1956-12-01), Thompson
patent: 3098971 (1963-07-01), Richardson
patent: 3384892 (1968-05-01), Postman
patent: 3493955 (1970-02-01), Minasy
patent: 3518546 (1970-06-01), Augenblick et al.
patent: 3711848 (1973-01-01), Martens
patent: 3754226 (1973-08-01), Fearon
patent: 3895368 (1975-07-01), Gordon et al.
patent: 4063229 (1977-12-01), Welsh et al.
patent: 4139844 (1979-02-01), Reeder
patent: 5030940 (1991-07-01), Siikarla
patent: 5942977 (1999-08-01), Palmer et al.
patent: 6104285 (2000-08-01), Stobbe
patent: 6163259 (2000-12-01), Barsumian et al.
Franklin Todd B.
Kelley Paul
Bugg George
Comm-Engines
Hofsass Jeffery
Horton John Wiley
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