Electronic proximity identification system
Identification system with vector phase angle detection
Proximity identification system with power aided identifier
Device for transmitting of binary data between a mobile data carrier and a stationary station
Transponder device Patent #: 4724427
ApplicationNo. 125660 filed on 11/25/1987
US Classes:340/10.34, Power up235/382, Permitting access235/382.5, Changeable authorization340/5.8, Authentication (e.g., identity)340/10.42Identification only
ExaminersPrimary: Yusko, Donald J.
Assistant: Palladino, Brian
Attorney, Agent or Firm
International ClassesG06K 005/00
Foreign Application Priority Data1986-11-25 FR
AbstractA reader identifies coded electronic badges without contact with the latter, by simple inductive coupling of inductances, the electrical supply of the badge being ensured from a voltage at high frequency F generated by the reader. The code of the badge, composed of a sequence of bits following one another at a frequency f very much less than F, is used to modulate a voltage of intermediate frequency fi comprised between f and F and the thus modulated voltage controls an electronic switch adapted to short-circuit a resonant circuit of the badge.