Signal transmission and tag reading circuit for an inductive reader
US5559507A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 30, 1993 |
| Grant date | Sep 24, 1996 |
| Priority date | — |
| Expiry date | Nov 30, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B13/2462
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A field coil signal transmission and tag reading circuit is disclosed for use in an inductive tag reader system. The circuit is coupled to an oscillator which provides a drive signal to a differential driver. The driver transforms the clock signal into first and second complementary drive signals. The drive signals are coupled to a field coil through a plurality of capacitors for inductively producing an output power signal. The capacitors are differentially coupled to the coil, so that each input of the coil is coupled to one of the clock signals through a separate capacitor. A bridge rectifier is coupled to the field coil opposite the capacitors for producing an output comprising a direct current element and an alternating current element superimposed on the DC element. A resistance-capacitance (R-C) filter, coupled to the bridge rectifier, provides a filtered rectifier output signal. The output signal can be decoded downstream of the R-C filter using several different decoding schemes known in the art.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.