Electronic identification system
US4242663A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 1, 1979 |
| Grant date | Dec 30, 1980 |
| Priority date | — |
| Expiry date | Feb 1, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG07C9/28
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
An electronic identification system includes common transceiver and signal processing apparatus, and relative small electronic circuitry, referred to as a "tag", secured to each item of a population to be identified. Each tag is assigned a multi-bit digital code which may or may not be unique. The common equipment determines whether any desired tag-bearing item is nearby by emitting a phase modulated radio frequency wave embodying the requisite tag code, and examining the output of a homodyne mixer, operating on a radar-like recovered reflection signal, for a predetermined signatory response. Such a response will be generated only by a tag circuit responding to a match between its stored encoding and that of the interrogation signal by changing the effective cross sectional reflecting area of the tag antenna.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.