Abstract: A circuit with variable capacitance includes a capacitance, wherein the capacitance includes a first partial capacitance and a second partial capacitance connected in parallel to the first partial capacitance, wherein a capacitance value of the first partial capacitance depends on a first bias of the partial capacitance, and a capacitance value of the second partial capacitance depends on a second bias of the second partial capacitance. The circuit with variable capacitance further includes a unit for providing the first bias and the second bias. With such a circuit with variable capacitance, it is possible to achieve a more linear and flatter characteristic tuning curve of the circuit with variable capacitance as compared to a conventional circuit with variable capacitance in a simple way.

Abstract: A demodulation arrangement for a radio signal is disclosed wherein an I/Q mixer converts the radio signal to a real and an imaginary component and supplies the components to a limiting circuit. The limiting circuit limits the amplitude of the signals applied to its inputs. A demodulator circuit receives the output of the limiting circuit and converts the signal components to a demodulated signal including a sequence of pulses. A pulse shaper circuit converts the pulses having pulse amplitudes that are greater than a first threshold value to output pulses having a predetermined first amplitude. This reduces fluctuations in the pulse amplitudes, thus leading to a reduction in low-frequency interference and jitter in the data signal.

Abstract: A circuit with variable capacitance includes a capacitance, wherein the capacitance includes a first partial capacitance and a second partial capacitance connected in parallel to the first partial capacitance, wherein a capacitance value of the first partial capacitance depends on a first bias of the partial capacitance, and a capacitance value of the second partial capacitance depends on a second bias of the second partial capacitance. The circuit with variable capacitance further includes a unit for providing the first bias and the second bias. With such a circuit with variable capacitance, it is possible to achieve a more linear and flatter characteristic tuning curve of the circuit with variable capacitance as compared to a conventional circuit with variable capacitance in a simple way.

Abstract: A receiving arrangement for a radio signal includes a step-down mixer with a downstream signal processing chain and demodulator. An RSSI signal is obtained between the step-down mixer and the demodulator, for example in a limiter. The RSSI signal is high-pass filtered and supplied to a comparator in the form of a mean value thereof. The identification unit can detect as a function of the RSSI signal level whether no useful signal at all, an amplitude-modulated signal or a frequency-modulated signal is present. The demodulator is accordingly driven by a control unit. In accordance with the arrangement of the present invention it is possible, in a particularly simple and precise manner, to identify and correspondingly set a demodulator as a function of whether an amplitude-modulated or frequency-modulated signal is received.

Abstract: A demodulation arrangement for a radio signal is disclosed wherein an I/Q mixer converts the radio signal to a real and an imaginary component and supplies the components to a limiting circuit. The limiting circuit limits the amplitude of the signals applied to its inputs. A demodulator circuit receives the output of the limiting circuit and converts the signal components to a demodulated signal including a sequence of pulses. A pulse shaper circuit converts the pulses having pulse amplitudes that are greater than a first threshold value to output pulses having a predetermined first amplitude. This reduces fluctuations in the pulse amplitudes, thus leading to a reduction in low-frequency interference and jitter in the data signal.

Abstract: A crystal oscillator circuit has capacitors that govern the resonant circuit and are designed such that they can be connected and disconnected, for frequency adjustment. A respective compensation capacitor is connected opposite and in mirror-image form to these capacitors that govern the resonant circuit. This compensation capacitor influences only the dynamic operating point, but has virtually no effect on the oscillation frequency. In consequence, it is not possible to shift the operating point during adjustment of the oscillation frequency, thus ensuring stability of the oscillating system and operation at the desired operating point.

Abstract: A crystal oscillator circuit has capacitors that govern the resonant circuit and are designed such that they can be connected and disconnected, for frequency adjustment. A respective compensation capacitor is connected opposite and in mirror-image form to these capacitors that govern the resonant circuit. This compensation capacitor influences only the dynamic operating point, but has virtually no effect on the oscillation frequency. In consequence, it is not possible to shift the operating point during adjustment of the oscillation frequency, thus ensuring stability of the oscillating system and operation at the desired operating point.