Koninklijke Philips Corporation N.V.

U.S. Philips Corporation

Walter Einfeldt

Wolfgang Tobergte

Ernst Bretschneider

Alexander Kirchner

The invention relates to a method of generating a random-number sequence, and to a random-number generator, particularly for a chip card or a smart card. The random-number generator comprises:

Data-processing device and method of operating said device

The invention relates to a detector circuit ( ) for detecting short-lasting voltage pulses (spikes) in a power supply voltage (VDD). An integrator (INT) forms the average value (VDD_AV) of the power supply voltage (VDD) and a corresponding energy is stored in a first memory (MEM ). A comparator (COMP) compares the power supply voltage (VDD) with a predetermined voltage interval (&lsqb;Vref Vref ) and closes a switch (S) when the power supply voltage is outside this interval. The energy from the first memory (MEM ) then flows into a second memory (MEM ) via the switch (S) and a delay circuit (DELAY). When the energy in the second memory (MEM ) exceeds a threshold value, an output stage (OUT) is thereby activated, whose output supplies a signal (SPIKE_DET) indicating a voltage spike.

Detector circuit for detecting voltage spikes

Contactless transmission of information from a passive transponder to a base station takes place in known manner by load modulation in the transponder. The coils of resonant circuits in the base station and in the transponder are coupled to one another, both resonant circuits being tuned as well as possible to the carrier frequency of the base station so that the load modulation of the resonant circuit in the transponder influences the current in the resonant circuit of the base station. Because the two resonant circuits often are not tuned exactly to one another in practice and the transponder is also liable to be moved during the information transmission, it may occur that no signal is recovered by conventional demodulation in the base station. Therefore, according to the invention it is proposed to demodulate an imaginary component and a real component, or different combinations thereof, separately from the antenna signal in the base station and to combine these components by way of a logic circuit which provides notably mutual latching of the two channels. This enables more reliable recovery in the base station of the information transmitted by the transponder.

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Uetersen, Germany

Walter Einfeldt