Method and circuit of an actively transmitting tag
US9760822B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 14, 2014 |
| Grant date | Sep 12, 2017 |
| Priority date | — |
| Expiry date | Apr 16, 2034 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B5/26
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An actively transmitting tag detects a shift of a phase of an antenna signal (as) with regard to a phase of a transmitted signal (ts) in time intervals with a length of one half-period of a subcarrier, in which time intervals it transmits high-frequency wave packets with their phase being inverted according to a communication protocol at the ends of said half-periods. Generation of said wave packets is controlled by said phase shift in a way that said phase shift retains its absolute value at transitions into subsequent half-periods. Synchronizing the tag's transmission to a received interrogator signal carried out even during tag's transmitting enables the tag to transmit according to protocol ISO 14443 B by inverting a phase at transitions between said half-periods. Said synchronizing is carried out although no time window without a tag transmitting exists within the transmitted data frame.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.