Abstract: A system and method are provided for operating a magnetic resonance tomograph. A transmitter of the magnetic resonance tomograph transmits a predetermined test pulse with a reduced power. The magnetic resonance tomograph receives the test pulse with the local coil. A controller compares the received test pulse with a predetermined pulse response and emits a warning signal when the received test signal differs from the predetermined pulse response.

Abstract: A magnetic resonance tomography unit and a method for operating the magnetic resonance tomography unit are provided. The magnetic resonance tomography unit includes a transmitter for generating excitation pulses with a wavelength lambda, an antenna for emitting the excitation pulses, a feed line, and a voltage sensor. The voltage sensor is arranged on the feed line at an effective distance corresponding to a multiple of half the wavelength lambda from a feed point on the antenna.

Abstract: A radio-frequency control system for a magnetic resonance tomography system and a method for the operation thereof are provided. The radio-frequency control system includes a controller and a radio-frequency power amplifier with amplification between a signal input and a signal output of the radio-frequency power amplifier that is dependent on a predetermined frequency response. The controller determines a control pulse for multislice excitation and outputs the pulse to the signal input of the radio-frequency power amplifier. The controller determines a high-frequency power value for the control pulse in dependence on the predetermined frequency response of the radio-frequency power amplifier.

Abstract: A magnetic resonance tomography unit and a method for operating the magnetic resonance tomography unit are provided. The magnetic resonance tomography unit includes a transmitter for generating excitation pulses with a wavelength lambda, an antenna for emitting the excitation pulses, a feed line, and a voltage sensor. The voltage sensor is arranged on the feed line at an effective distance corresponding to a multiple of half the wavelength lambda from a feed point on the antenna.

Abstract: A system and method are provided for operating a magnetic resonance tomograph. A transmitter of the magnetic resonance tomograph transmits a predetermined test pulse with a reduced power. The magnetic resonance tomograph receives the test pulse with the local coil. A controller compares the received test pulse with a predetermined pulse response and emits a warning signal when the received test signal differs from the predetermined pulse response.

Abstract: An apparatus and a method for detecting an antenna coil with a non-active detuning apparatus are provided. The apparatus has a transmitter, an antenna, an amplitude meter, and a controller. The controller actuates the transmitter such that the transmitter emits radio-frequency signals with different predetermined amplitudes via the antenna. The controller acquires testing amplitudes with the amplitude meter as a function of the emitted signal and determines a testing relationship between the predetermined amplitudes and the acquired testing amplitudes. If the determined testing relationship deviates from a predetermined reference relationship, a signal is output.

Abstract: A radio-frequency control system for a magnetic resonance tomography system and a method for the operation thereof are provided. The radio-frequency control system includes a controller and a radio-frequency power amplifier with amplification between a signal input and a signal output of the radio-frequency power amplifier that is dependent on a predetermined frequency response. The controller determines a control pulse for multislice excitation and outputs the pulse to the signal input of the radio-frequency power amplifier. The controller determines a high-frequency power value for the control pulse in dependence on the predetermined frequency response of the radio-frequency power amplifier.

Abstract: A method for emitting a sequence of high frequency pulses that may have different envelopes in a magnetic resonance tomography system is provided. A digital instruction signal that specifies the envelope for the high frequency pulses that are to be emitted is received. A digital control signal is transmitted to a high frequency unit for generating high frequency pulses, depending on the instruction signal. A test signal that allows notification of a current overload situation is received. The current control signal is reduced if the test signal indicates an overload situation.

Abstract: An apparatus and a method for detecting an antenna coil with a non-active detuning apparatus are provided. The apparatus has a transmitter, an antenna, an amplitude meter, and a controller. The controller actuates the transmitter such that the transmitter emits radio-frequency signals with different predetermined amplitudes via the antenna. The controller acquires testing amplitudes with the amplitude meter as a function of the emitted signal and determines a testing relationship between the predetermined amplitudes and the acquired testing amplitudes. If the determined testing relationship deviates from a predetermined reference relationship, a signal is output.

Abstract: A B1 magnetic field may be regulated during a magnetic resonance tomography (MRT) imaging sequence.

Abstract: A two-channel magnetic resonance tomography system is provided with a regulation circuit for an amplification system in order to be able to take into account different load situations of the MRI system in a flexible and efficient manner. It is thus possible to improve the MRI measurements greatly if the MRI system is set to the respective load situation beforehand by an idle state measurement. The adaptation may optionally also be carried out during the MRI measurement. Therefore, a multiplicity of completely different load situations may be taken into account in an optimized manner by the regulation circuit.

Abstract: A method for monitoring a high-frequency transmit device of a magnetic resonance tomography system with a transmit antenna system having a plurality of transmit channels is provided. A reference transmit signal is output on different transmit channels of the transmit antenna system, respectively, at different time points, and a reference measurement signal induced by the reference transmit signal is measured on at least one of the other transmit channels using a measuring device assigned to the transmit channel. Based on the reference measurement signal, a phase deviation indicator value is determined. The phase deviation indicator value indicates a relative phase deviation between the measuring devices of the transmit channels in question.

Abstract: A two-channel magnetic resonance tomography system is provided with a regulation circuit for an amplification system in order to be able to take into account different load situations of the MRI system in a flexible and efficient manner. It is thus possible to improve the MRI measurements greatly if the MRI system is set to the respective load situation beforehand by an idle state measurement. The adaptation may optionally also be carried out during the MRI measurement. Therefore, a multiplicity of completely different load situations may be taken into account in an optimized manner by the regulation circuit.

Abstract: A method for monitoring a high-frequency transmit device of a magnetic resonance tomography system with a transmit antenna system having a plurality of transmit channels is provided. A reference transmit signal is output on different transmit channels of the transmit antenna system, respectively, at different time points, and a reference measurement signal induced by the reference transmit signal is measured on at least one of the other transmit channels using a measuring device assigned to the transmit channel. Based on the reference measurement signal, a phase deviation indicator value is determined. The phase deviation indicator value indicates a relative phase deviation between the measuring devices of the transmit channels in question.

Abstract: A method for emitting a sequence of high frequency pulses that may have different envelopes in a magnetic resonance tomography system is provided. A digital instruction signal that specifies the envelope for the high frequency pulses that are to be emitted is received. A digital control signal is transmitted to a high frequency unit for generating high frequency pulses, depending on the instruction signal. A test signal that allows notification of a current overload situation is received. The current control signal is reduced if the test signal indicates an overload situation.

Abstract: A B1 magnetic field may be regulated during a magnetic resonance tomography (MRT) imaging sequence.

Abstract: A mobile radio telephone includes a transmitter output stage and an antenna. An impedance matching network is inserted between the transmitter output stage and the antenna. The matching network has a transformation factor (T) for adjusting the transmitter load impedance (ZPA) to match with the antenna input impedance (ZAAnt). The impedance matching network includes at least two impedance transformers that form at least two transformation factors by alternatively connecting in parallel the two impedance transformers.

Abstract: Transmitter including a controllable power amplifier, whose output signal is fed back to a control input of the power amplifier via a detector device which produces a detector signal for detecting the output power of the power amplifier, and comprising a signal generator for producing a control signal which is used for forming the output signal and has rising and falling edges. A control signal is derived from the comparison of the detector signal with the reference value which control signal has a rising edge and thus also terminates the increase of the transmitted power. The transmitter is used in time-division multiplex systems, more specifically, in mobile and fixed stations in a mobile radio system according to the GSM standard.

Abstract: The invention relates to a circuit arrangement for frequency synthesis with a phase control circuit (1) which comprises a first phase discriminator (3) for receiving a reference signal and an output signal supplied by a first frequency divider (6) with a division ratio k, a low-pass filter (4) coupled to the output of the first phase discriminator (3), and an oscillator (5) coupled to the output of the low-pass filter (4) for generating an output signal which can be supplied to the first frequency divider (6). At least one further branch (2) with a further phase discriminator (8) and a further frequency divider (9) which is to be released and which has a division ratio k is present. The further phase discriminator (8) coupled to the input of the low-pass filter (4) is designed for receiving the reference signal delayed by a delay element (10) and the output signal of the further frequency divider (9) provided for receiving the output signal of the oscillator (5).

Abstract: The present invention provides, as compounds, the substituted 4,5-dihydroxy-imidazolidine-2-thiones of the general formula ##STR1## in which R.sup.1, R.sup.2 and R.sup.3, which are selected independently of one another each represent hydrogen, optionally substituted alkyl, optionally substituted alkoxy or halogen andR.sup.4 represents optionally substituted alkyl, cycloalkyl or alkenyl.It has been found that the compounds of this invention have a powerful ectoparasiticidal action, in particular against acarids.