Device for identification by proximity
US4893118A · kind A · utility
46Cited by
5References
4Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Nov 25, 1987 |
| Grant date | Jan 9, 1990 |
| Priority date | — |
| Expiry date | Nov 25, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG07C9/29
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A 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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.