Title:
SENSING METHOD FOR TRANSFER DURING DATA TRANSMISSION
Document Type and Number:
Japanese Patent JP3722216
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To sense the transfer of a signal in a bidirectional communication, and to prevent unlocking caused by the false transfer of a signal in the certifying process for unlocking an automobile.
SOLUTION: In a sensing method for a transfer or wiretapping in bidirectional non-contact data transmission, an amplitude attenuation (A1) generated in out-going data transmission is compared with an amplitude attenuation (A2) generated in its returne transmission. The amplitude attenuation (A1) generated in outgoing route is coded together with its answering signal. When the magnitudes of the attenuation determined by the comparison are equal to each other, the possibility of a transfer process can be excluded. In order to increase further the certainty of this system, a carrier frequency (F2) of a request signal is also compared with a carrier frequency (F21) of the answering signal. An ID code can be also incorporated in the signals.
Inventors:
Werner Bratz
Application Number:
JP2002036539A
Publication Date:
November 30, 2005
Filing Date:
February 14, 2002
Export Citation:
Assignee:
ATMEL Germany Gmbh
International Classes:
B60R25/00; G07C9/00; H04B1/59; H04B5/00; H04L5/14; (IPC1-7): H04L5/14; H04B1/59; H04B5/00
Domestic Patent References:
| JP2001057691A | ||||
| JP2000156718A | ||||
| JP2001127672A | ||||
| JP2001022905A | ||||
| JP11066250A | ||||
| JP2002152191A | ||||
| JP7162335A | ||||
| JP2000054707A | ||||
| JP2001230715A |
Foreign References:
| WO2000005696A1 |
Attorney, Agent or Firm:
Keishiro Takahashi
Mikio Kuruyama
Mikio Kuruyama