Pulse or digital communications – Transmitters
Reexamination Certificate
2005-01-11
2005-01-11
Fan, Chieh M. (Department: 2634)
Pulse or digital communications
Transmitters
C342S042000, C340S005100, C340S005620
Reexamination Certificate
active
06842493
ABSTRACT:
In a bi-directional contactless data transmission, a procedure aims to prevent the communication distance from being extended by unauthorized persons using radio repeaters. The procedure involves establishing a fixed relationship of a selected physical parameter of an electromagnetic signal. For example, the frequency of the signal received by a transponder is multiplied with a number to provide a different frequency, and a response signal having this different frequency is transmitted back to a base unit. In the base unit, the received frequency of this response signal is divided by the same number and the result is compared to the frequency of the originally emitted signal. If the resulting difference is below a preset threshold, then there is a fixed frequency relationship between the two signals, the process concludes that there has been no unauthorized extension of the communication distance by using repeaters, and the further authentication is carried out.
REFERENCES:
patent: 4229741 (1980-10-01), Groth, Jr.
patent: 4364043 (1982-12-01), Cole et al.
patent: 4630044 (1986-12-01), Polzer
patent: 5193114 (1993-03-01), Moseley
patent: 5504485 (1996-04-01), Landt et al.
patent: 5723911 (1998-03-01), Glehr
patent: 5838074 (1998-11-01), Loeffler et al.
patent: 5862225 (1999-01-01), Feldman et al.
patent: 3820353 (1989-12-01), None
patent: 3928571 (1990-03-01), None
patent: 4020445 (1992-01-01), None
patent: 4213880 (1993-04-01), None
patent: 4205827 (1993-09-01), None
patent: 19827722 (1999-12-01), None
“Ein Vielseitig Einsetzbares Schlüssellosses Zentral-Verriegelungsystem” (A Keyless Central Locking System With Varied Applications), published by VDI, Germany, VDI Report No. 1415, by Schmitz et al., 1998; pgs. 259 to 279.
Blatz Werner
Schwarzmueller Marco
Atmel Germany GmbH
Fan Chieh M.
Fasse W. F.
Fasse W. G.
Perilla Jason M.
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