Electronic data communications system
First Claim
1. In a data transmission system for the non-contact transmission of data between a station and a portable data card, wherein the station includes:
- a station resonant circuit tuned to a first signal, anda demodulator for detecting a second signal superimposed on the first signal,and wherein the portable data transaction card includes;
a card resonant circuit responsive to the station resonant circuit for inductive coupling therewith so as to receive power from the station, anda card data communications circuit designed to be powered by said received power for loading the card resonant circuit thereby modulating the first signal with the second signal in response to first data stored within the card data communications circuit and, by means of said inductive coupling, enabling the first data to be transmitted from the card to the station;
the improvement wherein there is further provided;
a station data communications circuit within the station for deactuating the station resonant circuit and, by means of said inductive coupling, for deactuating the card resonant circuit in response to second data stored in the station data communications circuit, anda reading circuit within the data card including;
a pulse generation circuit coupled to the card resonant circuit for generating a pulse in response to a predetermined change in state of the power received by the card resonant circuit,a data converter coupled to the pulse generation circuit and responsive to said pulse, whereby the output of the data converter corresponds to said second data, andmeans for coupling the output of the data converter to the card data communications circuit so as to store said second data therein.
1 Assignment
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Accused Products
Abstract
A data transmission system for the non-contact transmission of data between a station and a portable data card, both of which contain resonant circuits tuned to the same frequency. The data card receives power from the station via inductive coupling of the two resonant circuits and transmits data to the station by means of a loading circuit on the card which loads the card resonant circuit and hence, by mutual coupling, the station resonant circuit in response to data stored within the card. The card also contains a reading circuit containing a pulse generation circuit which generates a pulse whenever the power received by the card resonant circuit is interrupted and then restored. Data may thus be transmitted from the station to the card by deactuating the station resonant circuit in response to the data to be transmitted, the resulting pulses generated within the card being interpreted as the transmitted data.
67 Citations
33 Claims
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1. In a data transmission system for the non-contact transmission of data between a station and a portable data card, wherein the station includes:
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a station resonant circuit tuned to a first signal, and a demodulator for detecting a second signal superimposed on the first signal, and wherein the portable data transaction card includes; a card resonant circuit responsive to the station resonant circuit for inductive coupling therewith so as to receive power from the station, and a card data communications circuit designed to be powered by said received power for loading the card resonant circuit thereby modulating the first signal with the second signal in response to first data stored within the card data communications circuit and, by means of said inductive coupling, enabling the first data to be transmitted from the card to the station; the improvement wherein there is further provided; a station data communications circuit within the station for deactuating the station resonant circuit and, by means of said inductive coupling, for deactuating the card resonant circuit in response to second data stored in the station data communications circuit, and a reading circuit within the data card including; a pulse generation circuit coupled to the card resonant circuit for generating a pulse in response to a predetermined change in state of the power received by the card resonant circuit, a data converter coupled to the pulse generation circuit and responsive to said pulse, whereby the output of the data converter corresponds to said second data, and means for coupling the output of the data converter to the card data communications circuit so as to store said second data therein. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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Specification