Abstract: A known method for parallel two-way symmetrical signal transmission by means of an isolating interface with a differentiating circuit comprising a capacitive barrier is improved. When restarting communication in the selected direction after a longer break, a pilot signal is conducted via the transmitting plates for the communication in the reverse direction and capacitive compensators to one of the receiving plates for communication in the selected direction. Threshold levels for comparisons of the signals of the first and second time derivative are decreased, the capacitance of capacitive compensators is then set to reduce output the output signal and finally communication is reestablished. Transmitting plates for communication in the reverse direction are now connected to the receiving plates for communication in the selected direction through the capacitive compensators with the capacitance adjusted as described above.

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: According to the method for regulating the supply voltage of an electronic circuit a regulating element with variable resistivity and the outer supply voltage being applied to an input terminal of said regulating element is controlled by an amplified difference between a reference voltage and a part of a regulated supply voltage whereat at first an instant, on which the regulating circuit and the electronic circuit start operating, is detected, and then such value of the reference voltage is set on said instant that the regulated supply voltage will equal a maximum allowable supply voltage of the electronic circuit and the supplied electronic circuit puts itself in a state of a maximum current consumption. Then an operating voltage drop across said regulating element is measured at regular time intervals and the reference voltage is then each time reduced by one degree until said operating voltage drop is below or equals a chosen most appropriate value of said operating voltage drop.

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: 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: 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: 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.

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 known method for parallel two-way symmetrical signal transmission by means of an isolating interface with a differentiating circuit comprising a capacitive barrier is improved. When restarting communication in the selected direction after a longer break, a pilot signal is conducted via the transmitting plates for the communication in the reverse direction and capacitive compensators to one of the receiving plates for communication in the selected direction. Threshold levels for comparisons of the signals of the first and second time derivative are decreased, the capacitance of capacitive compensators is then set to reduce output the output signal and finally communication is reestablished. Transmitting plates for communication in the reverse direction are now connected to the receiving plates for communication in the selected direction through the capacitive compensators with the capacitance adjusted as described above.

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 (ActComm-ProtlmplECI). 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: According to the method for regulating the supply voltage Uo of an electronic circuit a regulating element with variable resistivity and the outer supply voltage Ui being applied to an input terminal of said regulating element is controlled by an amplified difference between a reference voltage and a part of a regulated supply voltage Uo, whereat at first an instant, on which the regulating circuit and the electronic circuit start operating, is detected, and then such value of the reference voltage is set on said instant that the regulated supply voltage Uo will equal a maximum allowable supply voltage of the electronic circuit and the supplied electronic circuit puts itself in a state of a maximum current consumption.

Abstract: The measurement of a very low intensity of an electric current is carried out by 5 integrating the electric current over integration cycles having a time period ti and measuring a peak value of a sawtooth voltage at an integrated circuit output each time at the end of the integration cycle, whereat noise voltage components of a frequency above a cut-off frequency, which has a value of the order of magnitude (0,1×2?×ti)?1, being parts of a voltage of a noise generated in an operational amplifier comprised in the integrated circuit are filtered out of the said sawtooth voltage and noise components, which have the origin in the high-frequency voltage components of Johnson noise, which appear in the low-frequency spectral part of the sawtooth voltage as aliasing, are subtracted from a filtered sawtooth voltage.

Abstract: A voltage comparator where the difference of currents from transistors is converted into voltage, which is amplified and conducted to a gate terminal of a switching transistor. A source of a limiting transistor is connected to the gate terminal. The voltage at the gate terminal when the switching transistor is quiescent is equal to a value between eight and nine tenths of the switching voltage at the gate of the transistor, at which voltage the transistor triggers a switching in the output stage. A response to an input voltage change at one direction of the sign reversal of the difference of the input voltages is fast. The voltage comparator is robust and reliable with regard to temperature variations.

Abstract: The measurement of a very low intensity of an electric current is carried out by integrating the electric current over integration cycles having a time period ti and measuring a peak value of a sawtooth voltage at an integrated circuit output each time at the end of the integration cycle, whereat noise voltage components of a frequency above a cut-off frequency, which has a value of the order of magnitude (0.1×2?×ti)?1, being parts of a voltage of a noise generated in an operational amplifier comprised in the integrated circuit are filtered out of the said sawtooth voltage and noise components, which have the origin in the high-frequency voltage components of Johnson noise, which appear in the low-frequency spectral part of the sawtooth voltage as aliasing, are subtracted from a filtered sawtooth voltage.

Abstract: Output currents from differentially connected transistors (t1, t2) in a voltage comparator are subtracted from each other and the current difference is converted into voltage, which is amplified and conducted to a gate terminal (gtst) of a switching transistor (t7) at the input of an output stage. A source of a limiting transistor (t8?), whose gate is connected to a terminal (vsn) of the low supply voltage through two series-connected and diode-connected transistors (t8?, t8??) is connected to the gate terminal (gtst). The voltage at the gate terminal (gtst) when the switching transistor (t7) is quiescent is equal to a value between eight and nine tenths of the switching voltage Vsw at the gate of said transistor, at which voltage said transistor triggers a switching in the output stage. Said transistors are of the same type with a similar geometry and they operate in similar current conditions.

Abstract: An attack is activated in a receiver amplifier of an interrogator whenever an amplified input signal exceeds an attack threshold voltage value Vatt, and the receiver amplifier at least during a waiting period, the length of which preferrably equals the double length of the longest time interval between adjacent pulses in a transponder data wave packet, after the end of the attack does not respond in the sense of setting the gain. However, the amplifier responds with a decay activated after the lapse of the waiting period, which started when the instantaneous amplified signal value for the last time after the end of the attack exceeded a waiting threshold voltage level Vw. The decay rate is of the same order of magnitude as the attack rate. The improved method for automatically setting the gain renders it possible that the interrogator receiver within the non-contacting identification system practically does not change the essential characteristics of the input signal.

Abstract: In a non-contacting smart card interrogator (1) a first end (A) of an eighth-wave transmission line (13) is connected to a terminal connecting a first receiver (16) to a transmission line (14), and to a second end (B) of the transmission line (14) the carrier wave generator (11) is connected. To the first end (A) of the eighth-wave transmission line (13) the first amplitude demodulation receiver (16) and to the second end (B) thereof a second amplitude demodulation receiver (16?) are connected. In the non-contacting smart card interrogator of the invention an effective use of amplitude demodulation is made possible by changing the phase modulation into an amplitude one by means of a passive element, whereby, however, no noise source has been introduced into the system.

Abstract: An attack is activated in a receiver amplifier of an interrogator whenever an amplified input signal exceeds an attack threshold voltage value Vatt, and the receiver amplifier at least during a waiting period, the length of which preferrably equals the double length of the longest time interval between adjacent pulses in a transponder data wave packet, after the end of the attack does not respond in the sense of setting the gain. However, the amplifier responds with a decay activated after the lapse of the waiting period, which started when the instantaneous amplified signal value for the last time after the end of the attack exceeded a waiting threshold voltage level Vw. The decay rate is of the same order of magnitude as the attack rate. The improved method for automatically setting the gain renders it possible that the interrogator receiver within the non-contacting identification system practically does not change the essential characteristics of the input signal.

Abstract: A transmission of a signal through an isolation interface with a capacitive barrier is performed so that in an input circuit of the interface by integrating with an appropriate time constant the slope rates of the edges of signal replicas U1o± of the transmitted input signal Ui are adjusted and that the said signal replicas are differentiated either in an appropriate differentiating unit, whereat the time constants of these differentiating units are shorter than the rising and falling-off times of the signal replicas and are advantageously in the order of magnitude of 1 nanosecond or below. Therefore, in a circuit on the output side of the capacitive barrier no amplifier in front of voltage comparators is needed, which makes it possible that the pulse width is maintained extremely precisely. The data transmission is immune from the fast variation in the order of magnitude of 10 kV/&mgr;s of the potential difference between the voltage supplying sources for the input and the output circuits.

Abstract: In a non-contacting smart card interrogator (1) a first end (A) of an eighth-wave transmission line (13) is connected to a terminal connecting a first receiver (16) to a transmission line (14), and to a second end (B) of the transmission line (14) the carrier wave generator (11) is connected. To the first end (A) of the eighth-wave transmission line (13) the first amplitude demodulation receiver (16) and to the second end (B) thereof a second amplitude demodulation receiver (16′) are connected. In the non-contacting smart card interrogator of the invention an effective use of amplitude demodulation is made possible by changing the phase modulation into an amplitude one by means of a passive element, whereby, however, no noise source has been introduced into the system.