Abstract: The invention relates to an HF system that comprises an HF device (5), particularly an HF lamp, as well an HF spark-plug or similar HF plasma application, and an HF signal-incoupling device (3) for operating said HF device (5). The HF system comprises an oscillator (7) for generating an HF signal to operate said HF device (5), and said system is characterised in that it comprises means (15) for generating a voltage signal (Uprop) that is proportional to the degree of adaptation of the HF device, on the basis of the HF signal generated by the oscillator (7) and a signal reflected by said HF device. Moreover, the system is characterised in that it comprises a device (27), preferably without a microprocessor, for generating a control signal (UA) for adapting the oscillator (7) output-frequency on the basis of the voltage signal (Uprop) which is proportional to the degree of adaptation of the HF device (5).

Abstract: The invention relates to an HF system that comprises an HF device (5), particularly an HF lamp, as well an HF spark-plug or similar HF plasma application, and an HF signal-incoupling device (3) for operating said HF device (5). The HF system comprises an oscillator (7) for generating an HF signal to operate said HF device (5), and said system is characterised in that it comprises means (15) for generating a voltage signal (Uprop) that is proportional to the degree of adaptation of the HF device, on the basis of the HF signal generated by the oscillator (7) and a signal reflected by said HF device. Moreover, the system is characterised in that it comprises a device (27), preferably without a microprocessor, for generating a control signal (UA) for adapting the oscillator (7) output-frequency on the basis of the voltage signal (Uprop) which is proportional to the degree of adaptation of the HF device (5).

Abstract: The present invention relates to an adjustable circuit for filtering a transmission channel of an RFID signal and for suppressing a carrier signal in the reception path between an input gate and an output gate, including at least one adjustable oscillator for generating an oscillator signal, at least one input mixing stage cooperating with the oscillator for mixing an input signal by means of the oscillator signal to an intermediate frequency and a blocking device arranged downstream of the input mixing stage or the input mixing stages for suppressing the carrier signal at the intermediate frequency.

Abstract: A matching network for matching an antenna to a transmitter or receiver comprises an input port for receiving high-frequency power, an output port and a switchable impedance transformation circuit, which is connected between the input port and the output port. The impedance transformation circuit comprises a CMOS switch in a high-frequency path, which has a first switching state and a second switching state. The impedance transformation circuit is implemented to match a first impedance applied to the output port to a first predetermined impedance in the first switching state, and to match a second impedance applied to the output port to a second predetermined impedance in the second switching state. The inventive matching network allows a particularly good utilization of power provided by a transmitting amplifier or an antenna.

Abstract: The invention relates to a compensation circuit for suppressing the crosstalk between a transmission path and a reception path of an RFID-reader unit, including a device for coupling out a signal portion of a carrier signal from the transmission path into a compensation path, the compensation path having at least one variable phase shifter and at least one variable attenuator for varying the signal portion in the phase and in the amplitude respectively, a device for coupling in the signal portion varied in the phase and in the amplitude from the compensation path into the reception path, a unit for determining the crosstalk existing in the reception path and a control unit for the variable phase shifter and the variable attenuator, which is in signal connection with the unit for determining the existing crosstalk.

Abstract: The present invention relates to an adjustable circuit for filtering a transmission channel of an RFID signal and for suppressing a carrier signal in the reception path between an input gate and an output gate, including at least one adjustable oscillator for generating an oscillator signal, at least one input mixing stage cooperating with the oscillator for mixing an input signal by means of the oscillator signal to an intermediate frequency and a blocking device arranged downstream of the input mixing stage or the input mixing stages for suppressing the carrier signal at the intermediate frequency.

Abstract: A matching network for matching an antenna to a transmitter or receiver comprises an input port for receiving high-frequency power, an output port and a switchable impedance transformation circuit, which is connected between the input port and the output port. The impedance transformation circuit comprises a CMOS switch in a high-frequency path, which has a first switching state and a second switching state. The impedance transformation circuit is implemented to match a first impedance applied to the output port to a first predetermined impedance in the first switching state, and to match a second impedance applied to the output port to a second predetermined impedance in the second switching state. The inventive matching network allows a particularly good utilization of power provided by a transmitting amplifier or an antenna.