Abstract: Data encoded in packets modulated onto a carrier wave is transmitted between a base station and a transponder. Each packet includes a header section that contains at least a reference symbol and that serves for adjusting one or more transmission parameters, and a further section such as a data section. The transponder transmits data back to the base station through modulation and backscattering of the carrier wave. During the transmission of the header section by the base station, the transponder transmits transponder operating information relating to the processing of data to be received and/or transmitted by the transponder, by corresponding modulation and backscattering of the carrier wave. In response to and dependent on the received transponder operating information, the base station adjusts at least one transmission parameter, whereby the highest data transmission rate within the capabilities of the particular transponder can be achieved.

Abstract: One or more transponders are selected by a base station out of a plurality of transponders. For this purpose an identification bit sequence (IB) that is or includes a random number bit sequence (ZB) is made available in the respective transponder and the base station transmits in a bit-by-bit fashion a selection bit sequence (AB) to the transponders. These sequences (IB or ZB) and (AB) are compared bit-by-bit in the respective transponder. The comparing is performed by way of a predeterminable comparing criterion to provide a comparing result in the form of a selection bit to which a bit value is assigned. The selection is then made depending on the bit value of the selection bit of the respective transponder.

Abstract: Data encoded in packets modulated onto a carrier wave is transmitted between a base station and a transponder. Each packet includes a header section containing at least a reference symbol, and a further section such as a data section. In the transponder, the time duration of the reference symbol is determined, and a parameter is adjusted dependent on the determined duration. The parameter determines at least a property, such as the time resolution, of the encoding and/or decoding operation, and may be the clock frequency of a counter circuit or the charging current of an RC-circuit used to determine the duration of the symbols. The parameter may initially be set to a minimum default value, which is increased if the determined duration is less than or equal to a specified threshold. Thereby, power consumption is minimized while ensuring reliable encoding and decoding over a large range of transmission distances.

Abstract: A circuit arrangement for phase modulation in an input circuit of a backscattering transponder includes a varactor and at most one capacitor connected in series between two antenna terminals, as well as a varactor control arrangement applying a control voltage to the varactor to selectively vary the capacitance thereof. One of the antenna terminals is connected directly to one of the varactor terminals without a capacitor therebetween. The other antenna terminal is connected either directly or through a capacitor to the other varactor terminal. One antenna terminal and/or one varactor terminal can be grounded. A DC-decoupling capacitor can be connected between a transponder circuit unit or a circuit ground and the common junction of the antenna terminal with the varactor terminal. The circuit arrangement is simple, economical, and uses minimal chip area by omitting further capacitors between the antenna terminals.

Abstract: A circuit arrangement for phase modulation in an input circuit of a backscattering transponder includes a varactor and at least one capacitor connected in series between two antenna terminals, and at least two voltage sources selectively connected through at least two switches to at least one terminal of the varactor. A control unit selectively opens and closes the switches in response to the data to be phase-modulated onto the backscattered signal. By selectively connecting the different voltage values of the respective voltage sources to the varactor terminal(s) through the switches, the capacitance of the varactor and correspondingly the input impedance of the input circuit are thereby varied, so as to provide respective different phase positions of the phase modulation.

Abstract: An integrated circuit is combined with a transponder to function either as a voltage or power supply for the transponder by extracting energy out of an electromagnetic field transmitted by a base station or as a detector in the transponder to act as a remote sensor. For this purpose the integrated circuit comprises diode rectifiers. Each of the diode rectifiers has a first and a second service terminal and a reference terminal. In order to reduce a parasitic impedance between the first service terminal and the reference terminal, the first service terminal of at least one rectifier diode is electrically connected to a reference potential such as ground. Parasitic diode characteristics are further reduced by surrounding the respective diode or diodes by an electrical conductor path also connected to the reference potential.

Abstract: A circuit arrangement for deriving electrical power from a received electromagnetic field to power a transponder includes a detuning unit connected between two antenna terminals for limiting the power absorbed by the antenna. The detuning unit includes a component having an impedance that passively varies or is actively varied dependent on the field strength of the field prevailing at the antenna. One arrangement of the detuning unit includes two varactor diodes connected anti-parallel between the antenna terminals. Another arrangement of the detuning unit includes a varactor arranged in series between two capacitors between the antenna terminals, a field strength detector, and a controllable voltage source connected to apply to the varactor a control voltage that varies depending on the detected field strength. Thereby, the input impedance varies depending on the field strength, to achieve impedance matching for a low field strength, and a mis-matched condition for a high field strength.

Abstract: For transmitting data, a receiving/backscattering arrangement receives, modulates and reflects or backscatters electromagnetic waves emitted by a base station. The modulation corresponds to the data to be transmitted and is carried out selectively using first and/or second different modulation methods depending on the received field strength of the received electromagnetic waves. Preferably, phase shift keying is used especially or at least at low field strengths at far range, while amplitude shift keying is used additionally or alternatively for high field strengths at close range. The two modulation methods can be superimposed. A circuit arrangement includes two different modulator arrangements to perform the two modulation methods depending on the received field strength. The second modulator arrangement preferably comprises a multi-stage voltage multiplier circuit with a modulated switching device intervening in one of the stages to achieve the modulation.

Abstract: For transmitting data between a base station and a transponder, information packets modulated onto an electromagnetic carrier wave each include a header section, a middle section, and an end section. The data are encoded in the middle section using information symbols, e.g. representing digital “1s” and “0s”. The header section of at least the first packet defines the number and unique identifications of all of the symbols that will be used for encoding the data in the middle section of this and/or subsequent packets. This transmission protocol defined in the header section can be varied in subsequent packets to adaptively adjust the transmission rate depending on the existing communication conditions and requirements such as high frequency regulations prescribed by national law. The transmission rate can be considerably increased, in comparison to a transmission rate that would otherwise be necessary for achieving a reliable transmission even under unfavorable conditions.

Abstract: A receiving/backscattering arrangement for carrying out a contactless data transmission includes an integrated circuit having two antenna contacts, a series arrangement of three high quality capacitances connected between the two antenna contacts, whereby the middle capacitance is an MOS varactor, a controllable variable voltage source connected across the MOS varactor, and a control unit that controls the voltage source. The receiving/backscattering arrangement is especially a passive transponder with a rectifier connected between the antenna contacts, or a semi-passive transponder including a battery or solar cell, to provide the required supply voltage for the circuit. The arrangement achieves a large communication range, for receiving and modulating an interrogation signal, and backscattering the modulated response signal with a high efficiency and low losses. The integrated circuit structure is compact and economical.

Abstract: In the previously known methods for tuning the antenna resonant circuit, in the case of passive transponders, their range in a high-frequency carrier field is generally limited to a few cm as the supply voltage for the integrated circuit gained from the carrier field falls very quickly with increasing distance.

Abstract: In a method of transferring data from a transponder to a reading device in a scanning identification system through load-modulation of an inquiry signal emitted by the reading device, with the transponder being initialized at the beginning of the reception of the inquiry signal and responding with the emission of the response signal, first a predetermined number of data bits that are not part of the response signal are transmitted, and a terminator sequence followed by the response signal are repeatedly transmitted, until the inquiry signal is interrupted. The time required by the reading device for building up the inquiry field is bridged by the predetermined number of data bits and, at the same time, the reading device is synchronized to the clock of the response signal. Through the terminator sequence, which indicates the beginning of a valid response signal, the response signal is already recognized correctly by the reading device during the first transfer.

Abstract: According to the known methods with wireless communication, only one information symbol is transmitted by means of a carrier wave. The different types of information are digitally coded and transmitted in the form of data words.

Abstract: The invention relates to a method for transmitting data in a system comprising a reader that creates an interrogation field which contains at least two transponders that, after a start signal has been given in the interrogation field, transmit through load modulation of the interrogation field a uniquely assigned bit sequence back to the reader.