Data communication system harnessing frequency shift keyed magnetic field
US6349116B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 12, 2000 |
| Grant date | Feb 19, 2002 |
| Priority date | — |
| Expiry date | Oct 12, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V15/00
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A non-propagating magnetic field-based communication system transmits and receives digital data within a limited coverage area environment. The system includes a compact transmitter unit, such as that contained in an ‘tracking’ tag affixed to an object, and a digital detector/demodulator unit. In order to generate and FSK-modulate a non-propagating magnetic field in accordance with modulation signals representative of the digital data, the transmitter unit contains a magnetic field coil and one or more capacitors controllably switched in circuit with the coil in accordance with the data, so as to change the resonant frequency of an inductor-capacitor transmitter resonant circuit. The receiver unit includes a magnetic field-sensing coil in circuit with a capacitor, to form a receiver resonant circuit that resonates at a frequency between the FSK frequencies modulated by the transmitter unit. A digital receiver/demodulator detects whether received frequencies are valid FSK frequencies and derives digital data using differences between valid detected FSK frequencies.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.