Abstract: An actively transmitting tag detects a shift of a phase of an antenna signal (as) with regard to a phase of a transmitted signal (ts) in time intervals with a length of one half-period of a subcarrier, in which time intervals it transmits high-frequency wave packets with their phase being inverted according to a communication protocol at the ends of said half-periods. Generation of said wave packets is controlled by said phase shift in a way that said phase shift retains its absolute value at transitions into subsequent half-periods. Synchronizing the tag's transmission to a received interrogator signal carried out even during tag's transmitting enables the tag to transmit according to protocol ISO 14443 B by inverting a phase at transitions between said half-periods. Said synchronizing is carried out although no time window without a tag transmitting exists within the transmitted data frame.

Abstract: An RFID transponder device has antenna terminals for coupling an antenna system to the device. A transmitter and a receiver are coupled to the antenna terminals. The device has at least one damping resistance connected to at least one of the antenna terminals. The at least one damping resistance is connected, depending on a voltage swing at the antenna terminals during a transmission burst period, either together with a serially connected switch in parallel to the antenna terminals that are coupled to the receiver, or together with a parallel connected switch between one of the antenna terminals and a terminal of the transmitter. A damping control is configured to activate the at least one damping resistance during a damping period after the transmission burst period by controlling the respective switch.

Abstract: An RFID transponder device has antenna terminals for coupling an antenna system to the device. A transmitter and a receiver are coupled to the antenna terminals. The device has at least one damping resistance connected to at least one of the antenna terminals. The at least one damping resistance is connected, depending on a voltage swing at the antenna terminals during a transmission burst period, either together with a serially connected switch in parallel to the antenna terminals that are coupled to the receiver, or together with a parallel connected switch between one of the antenna terminals and a terminal of the transmitter. A damping control is configured to activate the at least one damping resistance during a damping period after the transmission burst period by controlling the respective switch.

Abstract: A microprogram for performing communication between an RFID smart tag and external digital sensors (EDS1, EDSK) is loaded in a buffer (Bu). A hard-wired dedicated processing unit (DPU) of the tag reads, decodes and executes said microprogram through the digital communication interface (DCI). The sensor data is stored at beginning locations of said buffer (Bu), wherefrom they are read by an RFID interrogator. The tag functionality in an application is settable with the RFID interrogator to an automatic data logger or RFID wireless sensor. The tag is adjustable to various types of digital sensors from various manufacturers. A hardwired dedicated processing unit makes it possible that the tag saves more energy, has smaller dimensions and is faster.

Abstract: An RFID transponder device has antenna terminals for coupling an antenna system to the device. A transmitter and a receiver are coupled to the antenna terminals. The device has at least one damping resistance connected to at least one of the antenna terminals. The at least one damping resistance is connected, depending on a voltage swing at the antenna terminals during a transmission burst period, either together with a serially connected switch in parallel to the antenna terminals that are coupled to the receiver, or together with a parallel connected switch between one of the antenna terminals and a terminal of the transmitter. A damping control is configured to activate the at least one damping resistance during a damping period after the transmission burst period by controlling the respective switch.

Abstract: A radio frequency system has a first and a second antenna terminal, a radio frequency transceiver coupled to the antenna terminals, a rectifier connected to the antenna terminals at its input side and a voltage limiter. The voltage limiter comprises a first and a second input terminal connected to the antenna terminals, and a first and a second diode element connected between the first respectively the second input terminal and a bias terminal. A regulation transistor is connected between the bias terminal and the reference potential terminal. A voltage controller has a reference input for receiving a reference signal, a feedback input connected to the bias terminal and a control output for providing a control potential to a control terminal of the regulation transistor on the basis of the reference signal and a signal at the bias terminal.

Abstract: A method is performed for a signal transmitted by an RFID interrogator being a radiofrequency electromagnetic sine wave. An amplitude noise contribution RSdAN to a demodulated received signal RSd within a frequency interval of a low-pass filter is determined by means of a measured demodulated transmitted signal TSd as RSdAN=k.TSd in that a dc component DCRS in said demodulated received signal RSd and a dc component DCTS in said demodulated transmitted signal TSd are measured and a conversion factor k is determined as k=DCRS:DCTS. A receiver output signal O is continuously generated out of the received signal by subtracting said amplitude noise contribution RSdAN from the demodulated received signal RSd, filtering the cleaned signal RSd-k.TSd by the low-pass filter and amplifying it. The conversion factor is determined in an exceptionally simplified way as said ratio of said dc components. No receiving interruptions are needed.

Abstract: A method of communication of an active smart RFID label with a user interrogator and a professional interrogator, said professional interrogator enabling a service provider to fully control said active smart RFID label and by means of which interrogator a content and a form of an extract of data, which are collected by a sensor, which is comprised of in the label, as well as a location within the label as location of said extract of data being collected by said label sensor, said location being accessible by the user interrogator are determined. A service user gets concisely acquainted with the service provided by the label by means of a widely used interrogator, whereat he cannot influence the data contained in the label or even its functioning neither needs any additional knowledge to communicate with said label.

Abstract: An actively transmitting tag detects a shift of a phase of an antenna signal (as) with regard to a phase of a transmitted signal (ts) in time intervals with a length of one half-period of a subcarrier, in which time intervals it transmits high-frequency wave packets with their phase being inverted according to a communication protocol at the ends of said half-periods. Generation of said wave packets is controlled by said phase shift in a way that said phase shift retains its absolute value at transitions into subsequent half-periods. Synchronizing the tag's transmission to a received interrogator signal carried out even during tag's transmitting enables the tag to transmit according to protocol ISO 14443 B by inverting a phase at transitions between said half-periods. Said synchronizing is carried out although no time window without a tag transmitting exists within the transmitted data frame.

Abstract: A memory access arbiter (MAA) in an RFID tag is connected to an unique address space (UAS), which comprises a non-volatile memory (NVM), a transferred data memory (TDM) and a status-information memory (SIM) storing information on the status of the transferred data memory (TDM). The transferred data memory (TDM) and the status-information memory (SIM) are volatile memories, e.g. of the RAM type having a memory capacity of 16 bits or 32 bits according to the standard of an applied RFID communication. The RFID tag of the invention provides for a faster communication between an interrogator and an external logic element by one order of magnitude, which is due to fast volatile memories for transferred data as well as for corresponding status information. A still higher communication rate is achieved by introducing a command that has not yet been standardized.

Abstract: Tuning an antenna circuit of an actively transmitting tag to a frequency of an interrogator carrier signal after the tag was inserted into a host device is accomplished by detecting presence of the interrogator carrier signal at a location of the actively transmitting tag and hereafter setting capacitances of capacitors and/or inductances of coils comprised in said antenna circuit in a way that resonance of said antenna circuit is established while the antenna circuit is excited by a magnetic field of said interrogator carrier signal. This allows automatic tuning of an antenna circuit of an actively transmitting tag after it was inserted together with a miniature card into a host device, such as a mobile telephone, personal digital assistant, tablet PC and similar devices.

Abstract: A method is performed for a signal transmitted by an RFID interrogator being a radiofrequency electromagnetic sine wave. An amplitude noise contribution RSdAN to a demodulated received signal RSd within a frequency interval of a low-pass filter is determined by means of a measured demodulated transmitted signal TSd as RSdAN=k·TSd in that a dc component DCRS in said demodulated received signal RSd and a dc component DCTS in said demodulated transmitted signal TSd are measured and a conversion factor k is determined as k=DCRS:DCTS. A receiver output signal O is continuously generated out of the received signal by subtracting said amplitude noise contribution RSdAN from the demodulated received signal RSd, filtering the cleaned signal RSd-k.TSd by the low-pass filter and amplifying it. The conversion factor is determined in an exceptionally simplified way as said ratio of said dc components. No receiving interruptions are needed.

Abstract: A calibrating output signal of the transmitter is generated in an interrogator in that a first output signal of a local oscillator is shallowly amplitude-modulated with a pilot signal having a frequency at which a contactless-card encodes data. A receiver reference signal is generated by combining the calibrating output signal of the transmitter and a signal whose carrier signal has a frequency equaling the frequency of the local oscillator signals, conducting the combined signal through a band-pass filter and amplifying it. A first and a second receiver output signals are cleared by subtracting the receiver reference signal, which has been attenuated by a calibrated factor and has a calibrated polarity, from the first and the second receiver output signal, respectively.

Abstract: A microprogram for performing communication between an RFID smart tag and external digital sensors (EDS1, EDSK) is loaded in a buffer (Bu). A hard-wired dedicated processing unit (DPU) of the tag reads, decodes and executes said micro-program through the digital communication interface (DCI). The sensor data is stored at beginning locations of said buffer (Bu), wherefrom they are read by an RFID interrogator. The tag functionality in an application is settable with the RFID interrogator to an automatic data logger or RFID wireless sensor. The tag is adjustable to various types of digital sensors from various manufacturers. A hardwired dedicated processing unit makes it possible that the tag saves more energy, has smaller dimensions and is faster.

Abstract: When communicating with a traditional interrogator of passive smart tags, an actively transmitting smart tag of the invention, even within a data frame being transmitted, observes a first phase (?i) being a phase of a voltage induced in a tag's antenna by an interrogator's high-frequency carrier signal and transmits wave packets in that it excites the antenna with a voltage having a phase (?t), which is always set at the beginning of transmission of each said wave packet shifted with respect to said first phase (?i) by the same phase angle (??). At ??=180° an amplitude of voltage across an interrogator's antenna, when some of said wave packets influence this antenna, attains the largest attainable interference rise. Miniature actively transmitting smart tags are enabled to wirelessly communicate with said traditional interrogator and a communication range of pocket-sized tags is herewith increased.

Abstract: An interrogator (Interrog) is additionally provided with a logic circuit (ActCommProt-ImplLCI) for implementing an active communication protocol and with a receiving second antenna (AI2) provided for an active communication. Said antenna is connected through an active receiver (AMActRecI) for receiving amplitude-modulated signals to said logic circuit (ActCommProtlmplLCI). A transmitting and receiving first antenna (AT1) in each transponder (Transp) is connected through an active receiver (AM-ActRecT) for receiving amplitude-modulated signals to a logic circuit (ActCommProt-ImplLCT) for implementing the active communication protocol, an output signal of which logic circuit is conducted through an active transmitter (AMActTransmT) for transmitting amplitude-modulated signals to a transmitting second antenna (AT2) for active communication. The transponder (Transp) is provided with a power supply circuit (SupplC).

Abstract: Output terminals (o1, o2) of a differentially excited transmitting circuit (TC) are connected through matching capacitors (MC1, MC2) to connecting terminals of the oscillatory circuit antenna (OCA) on the other side said connection terminals are directly connected to input terminals of a receiving circuit (RC). Each of the input terminals (i1, i2) of the receiving circuit (RC) is connected to an earthing terminal (m) of the integrated transceiver circuit (TRC) through a corresponding undervoltage-protection diode (UPD1, UPD2) determining a lower potential value of a received signal and a corresponding overvoltage-protection diode (OPD1, OPD2) determining an allowed upper potential value of the received signal exceeding said lower potential value by the highest possible voltage still allowable by the integrated transceiver circuit (TRC).

Abstract: An amplitude of a carrier signal at an output of an impedance matching block is measured as a first amplitude value. A value of the signal amplitude at the output of the impedance matching block is calculated as a second amplitude value that a signal resulting from amplitude modulation with said modulation factor from said carrier signal should assume, said carrying signal having an amplitude with the first amplitude value. A setting of a transmitter is changed to decrease the carrier signal amplitude at the output of the impedance matching block. An amplitude of a new carrier signal at the output of the impedance matching block is measured as a new amplitude value. The transmitter setting keeps changing so many times until the new amplitude value is equal to or lower than said second amplitude value or within a predetermined tolerance range around said second amplitude value.

Abstract: When communicating with a traditional interrogator of passive smart tags, an actively transmitting smart tag of the invention, even within a data frame being transmitted, observes a first phase (?i) being a phase of a voltage induced in a tag's antenna by an interrogator's high-frequency carrier signal and transmits wave packets in that it excites the antenna with a voltage having a phase (?t), which is always set at the beginning of transmission of each said wave packet shifted with respect to said first phase (?i) by the same phase angle (??). At ??=180° an amplitude of voltage across an interrogator's antenna, when some of said wave packets influence this antenna, attains the largest attainable interference rise. Miniature actively transmitting smart tags are enabled to wirelessly communicate with said traditional interrogator and a communication range of pocket-sized tags is herewith increased.

Abstract: A difference between an output current signal (mos) of the mixing circuit (MC) and a current from a controlled current source (CCS) is conducted to an input of an operational amplifier (A). A control voltage (cv) for said current source is a voltage at the output of the operational amplifier (A) being filtered by a low-pass filter, whose limiting frequency equals a low frequency limit of the modulation signal in the received signal (rs). The method is speeded up in that the limiting frequency of the low-pass filter is increased by two to three orders of magnitude at the beginning and is gradually lowered to said value. A rather short time duration of the transient process is achieved so that the working point with a low voltage of the DC component and low-frequency components is set at least five times faster than so far.