Contactless data transmission and receiving device with a synchronous demodulator
US6028503A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 4, 1997 |
| Grant date | Feb 22, 2000 |
| Priority date | — |
| Expiry date | Nov 4, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S13/758
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A transmission and receiving device for contact data transmission between the device and a transponder. The transmission and receiving device has an antenna resonant circuit, a synchronous demodulator, a measuring unit, a control unit, and a reference signal generator. In operation, the device and the transponder are inductively coupled to each other through the antenna resonance circuit of the device and an antenna resonance circuit in the transponder. In response to an interrogation by the device, the transponder sends a load modulated digital signal to the device. The synchronous demodulator detects digital response data contained in the load modulated digital signal. The measuring unit measures a phase shift between a reference signal generated by the reference signal generator and a resonance signal generated in the antenna resonance circuit in the device by the sent load modulated digital signal. The control unit controls the synchronous demodulator such that the synchronous demodulator changes its demodulation mode between amplitude demodulation and phase demodulation, in dependence of the measured phase shift.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.