Bruker Biospin Gmbh

Other

Michael Maixner

Diether Maier

Jacky Schaeffer

A microwave power amplifier arrangement for an electron paramagnetic resonance (EPR) system provides amplified microwave pulses having a microwave frequency in the X-band. The arrangement has a microwave input and a microwave output, and comprises at least one transistor amplifier device, and at least one switchable reflection device. A respective transistor amplifier device comprises a transistor amplifier device input directly or indirectly connected to the microwave input (), at least one transistor, and a transistor amplifier device output directly or indirectly connected to the microwave output. A respective switchable reflection device comprises a PIN diode and a lambda/4 line connected directly or indirectly to the transistor amplifier device output of at least one transistor amplifier device and to a first port of the PIN diode, with lambda being the wavelength of the microwave radiation within the lambda/4 line. A second port of the PIN diode is connected to ground.

Microwave power amplifier arrangement for a pulsed EPR system

A circuit assembly for correction of an input signal including a useful signal and a disturbance signal comprises: a voltage-controlled circuit having at least one voltage-controlled circuit element, an input interface and an output interface, a resistor connected upstream of the voltage-controlled circuit in series with the voltage-controlled circuit, an operational amplifier having a first amplifier input, a second amplifier input and an amplifier output, and a low-pass filter connected between the input interface of the at least one voltage-controlled circuit element and the first amplifier input of the operational amplifier, wherein the output voltage from the operational amplifier is fed back to the low-resistance terminal of the circuit element in that the low-resistance terminal of the at least one voltage-controlled circuit element is electrically connected to the amplifier output of the operational amplifier and to the second amplifier input of the operational amplifier.

Circuit assembly for correction of an input signal, use of the circuit assembly for detection of a physiological signal in a magnetic resonance (MR) system

A circuit arrangement for correcting an input signal that includes a useful signal with a useful frequency and an interference signal with an interference frequency comprises: a high-pass filter with a cut-off frequency; an inverting operational amplifier circuit connected downstream from the high-pass filter and connected in series with the high-pass filter; an active rectifier circuit connected downstream from the inverting operational amplifier circuit and connected in series thereto, with two parallel-connected line paths, wherein each line path comprises a rectifying element; and a summing amplifier circuit connected downstream from the rectifier circuit, wherein the summing amplifier circuit has an inverting input and a non-inverting input and each line path is electrically connected to one of the inputs of the summing amplifier circuit. This provides a simple and compact circuit arrangement with which interference signals can be effectively suppressed.

Circuit arrangement for correcting an input signal, and MRI-ET hybrid imaging device

A method for determining an electric current includes sending the electric current to be measured through a shunt arrangement that includes at least three identical resistors. The at least three identical resistors are thermally coupled to a common base plate and are electrically interconnected such that the electric current is at least partially divided such that a first local current through a first resistor is not equal to a second local current through a second resistor. The method also includes measuring, at the shunt arrangement, a first voltage and a second voltage via which the voltage dropping across a first resistor and across a second resistor are directly or indirectly determinable, and determining the electric current via the first voltage and the second voltage. A heating in the shunt arrangement generated by the electric current is at least partially taken into account in the determining the electric current.

Method for determining an electric current with a shunt arrangement, with compensation of heating in the shunt arrangement generated by the current

A microwave bridge circuit routes a transmission signal from a transmitter to a resonator and forwards the reception signal generated in the resonator to a receiver. It includes two electrical lines connected in parallel at a first circuit point TX, where the transmission signal is divided. The first electrical line has an attenuator for attenuating a first transmission signal portion. The second electrical line carries a second transmission signal portion and connects to the resonator at a second circuit point R, which divides it between section L, which runs from TX to R, and section L, which runs from R to a third circuit point RX. The length of the sections Land Lcorresponds to an odd integer multiple of one quarter of the wavelength of the transmission signal, and the divided transmission signal portions are combined at RX, where the reception signal is forwarded to the receiver.

Microwave bridge circuit for separating a transmission signal from a reception signal

A high-frequency interface circuit to direct transmitted signals to a connector (PR) for a HF arrangement in a transmit mode via an input (TX) of the high-frequency interface circuit and received signals from the connector (PR) to a receiver system in a receive mode via an output (RX) of the high-frequency interface circuit is presented. The circuit includes a transmit path (SP) linking the input (TX) to the connector (PR) and a receive path (EP) linking the connector (PR) to the output (RX). The receive path (EP) includes a first circuit (K), with at least a first switching element (S) that is electro-conductive in transmit mode and is electrically insulating in receive mode, connected to the connector (PR). In transmit mode, the first circuit (K) forms two parallel resonance circuits connected in series, while in receive mode, the first circuit (K) includes two series resonance circuits connected in parallel.

High-frequency interface circuit, high-frequency system and magnet resonance apparatus with a high-frequency interface circuit

A magnetic resonance (MR) device, having a gradient arrangement that includes a gradient coil (G) with an internal resistance (Rg), as well as an electric circuit for generating variable pulse-shaped currents through the gradient arrangement. The electric circuit has at least one low-voltage voltage source (V) for generating a voltage U&#x2264;100V, and a first circuit section in the electric circuit for current in the gradient coil in one direction and a second circuit section in the electric circuit for current in the gradient coil in a reverse direction to the first circuit section. This permits the generation of accurate square-wave current pulses, with a simultaneously short charging time of the auxiliary inductance.

Output stage for the generation of variable square-wave currents in an inductive load with no high-voltage supply

A nuclear magnetic resonance (NMR) resonator () comprising an inductive section () and a capacitive section (), wherein the inductive section () is band-shaped and surrounds a substantially cylindrical volume under investigation (), wherein the capacitive section () is formed from one or more discrete capacitor(s) (), and wherein the ends () of the band-shaped inductive section () are connected through one or several capacitor(s) () of the capacitive section (), is characterized in that the inductive section () is formed from a dielectric flexible foil () which is conductively coated on both sides and the ends () of the band-shaped inductive section () overlap, wherein the outer coating () of the inner end () is electrically conductingly connected to the inner coating () of the outer end (), with one or more through-connections () being provided in the area of the inner end () of the band-shaped inductive section (), and the outer coating () being connected in the area of the outer end () to the inner coating () in the area of the inner end () via one or more capacitor(s) () and one or several through-connection(s) (). The inventive NMR resonator for low-resolution NMR has a simple construction and provides NMR measurements of improved quality at low resonance frequencies.

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Bietigheim, Germany

Michael Maixner