Loading patent…
AssigneeWidex A/S
InventorsHenning Hougaard ANDERSEN, Soren KILSGAARD, Niels Ole KNUDSEN
Estimating the term…
In a monitoring device consisting of a reader and a data carrier, the reader (100) comprises a control unit (101), a memory (102), a digital signal generator (103), an output driver (104), resonance capacitors (105, 107) and a transmitter coil (106). The digital signal generator (103) is adapted for supplying a digital bit sequence selected among, at least two, bit sequences stored in the memory (102) whereby the strength of the magnetic field generated by the transmitter coil (106) can be varied dependent on the bit sequence selected by the control unit (101). The invention further provides a method of controlling the strength of a magnetic field generated by the reader of the monitoring device.
A monitoring device consisting of a reader and a data carrier, wherein the reader comprises a control unit, a memory, a digital signal generator, an output driver, a resonance capacitor and a transmitter coil, wherein the digital signal generator is adapted for supplying a digital bit sequence selected among, at least two, bit sequences stored in the memory, wherein the bit sequences stored in the memory are pulse density modulated in order to represent distorted analog sine signals with a fixed first-order harmonic frequency and variable amplitude, whereby the strength of the magnetic field generated by the transmitter coil can be varied dependent on the bit sequence selected by the control unit, and wherein the bit sequences stored in the memory have been optimized with respect to a characteristic of another harmonic frequency.
A method for controlling the strength of an inductive power transmission between a reader and a data carrier in a monitoring system by controlling the strength of a magnetic field generated by the reader of the monitoring device, said method comprising the steps of:
Dependencies are inferred from the claim text.