Wide dynamic range demodulator for smart cards or contactless tickets
US6828853B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jan 24, 2003 |
| Grant date | Dec 7, 2004 |
| Priority date | — |
| Expiry date | Jan 24, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K5/082
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A demodulator for an amplitude modulated alternating signal includes a peak detection circuit for extracting the reference modulating signal from the amplitude modulated alternating signal, and a first translation circuit for offsetting the level of the reference modulating signal by a value equal to the DC component to obtain an offset reference modulated signal. A comparison threshold generator circuit generates a comparison threshold to locate the start and the end of the modulation, and a comparator circuit compares the offset reference modulating signal with the comparison threshold for providing signals that cross the comparison threshold. An unregulated supply circuit provides a supply voltage to the different circuits.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.