Abstract: In an arrangement for conversion of an analog acquisition signal of an acquisition coil of a magnetic resonance apparatus into a digital signal, the output of the acquisition coil is connected with a low-noise amplifier such that the analog acquisition signal from the acquisition coil arrives at the amplifier. The amplifier is connected at the output side with a device for analog-digital conversion, such that the analog acquisition signal arrives at the device for analog-digital conversion as an amplified acquisition signal for analog-digital conversion. The device for analog-digital conversion is designed as a delta-sigma modulator that forms a digital data stream with a width of one bit from the amplified acquisition signal.

Abstract: A filter circuit arrangement for filtering of a radio-frequency signal has a first tunable filter and a phase regulation loop in order to hold the first tunable filter to a transmission phase constant relative to the frequency of the radio-frequency signal. The filter circuit arrangement has a second tunable filter arranged parallel to the first tunable filter in the phase regulation loop. The first tunable filter and the second tunable filter exhibit different attenuation characteristics and are fashioned and connected within the phase regulation loop so that: a capture range of the filter circuit arrangement, in which a tuning of the phase regulation loop to a radio-frequency signal to be filtered is possible is dominated by the attenuation characteristic of the second tunable filter, and so that the transmission behavior of the filter circuit arrangement in operation is dominated by the attenuation characteristic of the first tunable filter, given a tuned phase regulation loop.

Abstract: In a mixer circuit with a balanced frequency mixer with varactor diodes, a first input signal that exhibits a first input frequency can be fed to the frequency mixer via a first input. Furthermore, a second input signal that exhibits a second input frequency can be fed to the frequency mixer via a second input. The frequency mixer has at least two amplifier elements fashioned as varactor diodes. These amplifier elements mix the input signals with one another into a mix signal with a first signal component and a second signal component. The first signal component exhibits a first component frequency, the second signal component a second component frequency. The first component frequency is equal to the sum of the first and second input frequencies, the second component frequency is equal to the difference of the first and second input frequencies. An output signal that contains at least one of the signal components can be tapped via the output.

Abstract: An amplifier device including at least one operational amplifier, whereby a transformer is connected upstream from the input of the operational amplifier and the output signal of the operational amplifier or a signal generated from this output signal is fed back again to the input of the operational amplifier via a path with a predetermined resistance whereby the feedback signal is fed back before the input of the transformer whereby the transformer is designed or connected in a signal-inverting manner.

Abstract: In a circuit arrangement for generation of a reference signal with an oscillation generator, a phase-controlled filter and a frequency multiplier are arranged downstream from the oscillation generator. The frequency multiplier is connected with an output for emission of the reference signal.

Abstract: A multiband terminal is provided which operates in at least two frequency bands, wherein the terminal includes one transmit device and one receive device for each of the frequency bands, and further includes at least two antennas and one circuit arrangement for connecting the antennas with the transmit devices and/or the receive devices, the circuit arrangement being designed such that, at least for one of the frequency bands and during operation of such, the associated receive device is switched to a first of the antennas as a receive antenna and the associated transmit device is switched to a second of the antennas as a transmit antenna.

Abstract: Method for operating an RF power amplifier (100; 200) with an approximately linear characteristic by adjusting at least one operating parameter of the amplifier or at least one active component of this amplifier, wherein a minimum collector or drain current of the active component or, respectively, an amplifier stage and the input signal level of the RF power amplifier are controlled in dependence on the quotient of harmonic power and useful-signal power of the amplifier output signal.

Abstract: A method of controlling the amplification of a high-frequency signal, in particular an intermittent signal, in which a radio-frequency signal to be amplified is passed in a control loop to a variable-gain amplifier, the gain being controlled by an amplifier control signal, part of the amplified radio-frequency signal is coupled out via a directional coupler and passed to a power detector, the output voltage of which is passed for difference-forming with a control signal to inputs of a comparator circuit, the output voltage of which, as a gain control signal, is readjusted to increase the power output level, the readjustment continuing until the output voltage of the detector and the voltage of the control signal at the inputs of the comparator circuit compensate for one another.