Transponder
First Claim
1. A transponder for supplying a code to a base station by varying a radio-frequency signal coming from the base station in a rhythm that corresponds to the code, the transponder comprising identification code generation means for generating the code;
- rectifier means which are arranged for AC coupling with a radio-frequency signal for applying a supply voltage to the generation means, and which rectifier means comprise at least one circuit acting as a rectifier;
a modulation transistor having a main current path, and comprising a control electrode which is coupled for the reception of the code for producing a variable load of the rectifier means as a result of which the radio-frequency signal varies with said rhythm, the at least one circuit acting as a rectifier comprising the main current path of the modulation transistor, voltage adaptation means for adapting the voltage levels of the code and for supplying the code with the adapted voltage levels to the control electrode of the modulation transistor; and
further rectifier means for applying a separate supply voltage to the voltage adaptation means.
1 Assignment
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Accused Products
Abstract
An identification transponder (IDT) for supplying an identification code to a base station (BS) varies an RF signal transmitted by the base station (BS) in a rhythm that corresponds to the identification code. The identification transponder (IDT) has identification code generation means (IDCG) for generating the identification code, rectifier means (RTF) for AC coupling with the base station (BS) for applying a supply voltage (V1) to the identification code generation means (IDCG), a modulation transistor (TM), voltage adaptation means (VADPT) for adapting the voltage levels of the identification code and for supplying the code with adapted voltage levels to a control terminal of the modulation transistor (TM), and further rectifier means (FRTF) for the aforementioned AC coupling to the base station (BS) for applying a separate supply voltage (V2) to the voltage adaptation means (VADPT). The modulation transistor (TM) may perform two tasks: the task of rectifying the RF signal, and the task of supplying a variable load to the rectifier means (RTF). The variable load varies in the rhythm. As a consequence, the input current of the rectifier means (RTF) is varied in the rhythm, which in its turn varies the RF signal. This variation in the RF signal is detected in the base station (BS).
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Citations
7 Claims
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1. A transponder for supplying a code to a base station by varying a radio-frequency signal coming from the base station in a rhythm that corresponds to the code, the transponder comprising identification code generation means for generating the code;
- rectifier means which are arranged for AC coupling with a radio-frequency signal for applying a supply voltage to the generation means, and which rectifier means comprise at least one circuit acting as a rectifier;
a modulation transistor having a main current path, and comprising a control electrode which is coupled for the reception of the code for producing a variable load of the rectifier means as a result of which the radio-frequency signal varies with said rhythm, the at least one circuit acting as a rectifier comprising the main current path of the modulation transistor, voltage adaptation means for adapting the voltage levels of the code and for supplying the code with the adapted voltage levels to the control electrode of the modulation transistor; and
further rectifier means for applying a separate supply voltage to the voltage adaptation means. - View Dependent Claims (2, 3, 4, 5, 6, 7)
- rectifier means which are arranged for AC coupling with a radio-frequency signal for applying a supply voltage to the generation means, and which rectifier means comprise at least one circuit acting as a rectifier;
Specification