Data communication system and radio IC card system
US5949823A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 12, 1997 |
| Grant date | Sep 7, 1999 |
| Priority date | — |
| Expiry date | Sep 12, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/2271
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
An arrangement to realize the functions of a radio card system in which power is transmitted to perform data communication. According to such arrangement, a delay line and a clock regenerating circuit such as PLL circuit which are previously necessary for demodulation by PSK are not necessary, and thus functions of data communication are realized by minimum hardware construction, size, cost and power consumption. Further, in a data communication system in which electric power transmission using a signal of a frequency fp and digital data communication using a carrier wave of a frequency fs are performed by radio, fs and fp are in the relationship of fs=fp/N (where N is an integer) and a phase shift P when the phase of the carrier wave is modulated by PSK is (M.times.360.degree.)/N (where M, N are integers and P is preferably not equal to 180.degree.).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.