Antenna signal amplitude modulation method
US6700551B2 · kind B2 · utility
2Cited by
7References
8Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Sep 25, 2001 |
| Grant date | Mar 2, 2004 |
| Priority date | — |
| Expiry date | Mar 21, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03C1/36
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A method for modulating the amplitude of an antenna signal applied to an inductive-type antenna circuit by a control circuit having binary ports that can be set to high impedance and with a non-zero internal resistor. The signal providing the electric power supply of the antenna circuit is delivered by at least two ports of the control circuit, and the amplitude of the antenna signal is modulated by changing the output state of at least one of the ports. Particularly applied to contactless smart card readers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.