Non-contact system for sensing and signalling by externally induced intra-body currents
US5914701A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 6, 1997 |
| Grant date | Jun 22, 1999 |
| Priority date | — |
| Expiry date | Aug 6, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02D30/70
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A wireless system includes one or more transmitters and one or more remote receivers that are respectively coupled through one or more users and room ground. The transmitters each produce low-frequency, low power signals that, through capacitive coupling, pass as displacement currents into and from the body of the user, which acts as a conductive node. A receiver that couples capacitively to the user responds to the displacement currents and reproduces the signals. The transmitter includes a signal generator and a pair of electrodes. The signal generator produces modulated signals that vary the voltage between the electrodes, a first one of which is closely coupled capacitively to the user's body such that the "quasi-electrostatic" field resulting from the electrode potential causes a displacement current to pass to the user's body. The second electrode is oriented so that its coupling to the room ground is stronger than that of the first electrode, such that room ground acts as a return path for the current from the receiver. The signal generator may modulate the information to be transmitted using, for example, a pseudorandom code, to produce spread spectrum signals. This increas…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.