Transponders, Interrogators, systems and methods for elimination of interrogator synchronization requirement
US5541604A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 3, 1993 |
| Grant date | Jul 30, 1996 |
| Priority date | — |
| Expiry date | Sep 3, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L25/4902
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A Radio Frequency Identification (RFID) system having an interrogator (12) and a transponder (14). The interrogator has a first tuned circuit (28) of a powering frequency for sending a powering burst to a transponder (14), a filter/demodulator (64) for receiving an wireless, modulated RF response from a transponder (14). The interrogator (12) further has a second tuned circuit (29) in electrical communication with a modulator (48), the second tuned circuit (29) having a selected bandwidth about a communication frequency, the selected bandwidth not substantially overlapping the powering frequency and encompassing the bandwidth of the modulated carrier of the RF response. The interrogator also has a controller (16) in electrical communication with the filter/demodulator (64) and the tuned circuits (28,29) and capable of enabling the first tuned circuit (28) to send the powering burst during a first time period and of enabling the modulator (48) in electrical communication with the second tuned circuit (29) to receive the RF response during a second time period. The transponder has a tuned circuit (34), a tuning circuit (54,56) in electrical communication with the tuned circuit (34) f…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.