Transponder system with variable frequency transmission
US5450492A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 30, 1992 |
| Grant date | Sep 12, 1995 |
| Priority date | — |
| Expiry date | Oct 30, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG07C9/28
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An electronic identification system comprising a transmitter for generating an electromagnetic excitation signal, one or more portable transponders for storing variable identification data, and for transmitting an information signal containing the identification data upon entering the field. Transmission of the information signal is independent of the excitation signal in both time and frequency. A radio frequency receiver is provided for receiving the information signal and in response generating output signal representing the variable identification data contained in the information signal. The system overcomes two principle disadvantages associated with existing systems: and excitation frequency can be selected for optimum performance given the circumstances dictated by each application; an independent response channel can be selected according to the requirements of each installation or application, thereby allowing response signals to be transmitted by transponders at a frequency which differs form the frequency of an interfering signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.