Siemens Aktiengesellschaft

Siemens Aktiengesell Schaft

Ralph Meissner

Helmut Kess

Rainer Alfred Kuth

Norbert Krause

Walter Popp

Wolfgang Pritzel

Ludger Freisen

In an electrical assembly with an electrical or electronic component part that generates a noise signal with a disturbing frequency, a parallel resonant circuit tuned to the frequency is arranged in the immediate proximity of the component part.

LCD having noise counteracting parallel resonant circuit

A local antenna for transmitting and/or receiving radio frequency signals in a nuclear magnetic resonance imaging apparatus includes first and second sub-antennas which are axially spaced from each other. The sub-antennas each are composed of at least one conductor turn. An electrical series circuit is formed of the first sub-antenna, a capacitive element for shortening the path length effective for the radio frequency signal and of the second sub-antenna. The two sub-antennas have the same winding direction. A capacitor is connected in parallel with the series circuit. The respective capacitance values of the series capacitive element and the parallel capacitor are approximately the same. For constructing a local antenna system especially suitable for mammography, two such local antennas are arranged side-by-side and are electrically connected in parallel. The series capacitive elements of the two local antennas face each other.

Local antenna with homogeneous sensitivity for a nuclear magnetic

A nuclear magnetic resonance apparatus which is capable of identifying either spectra or images of an examination subject uses a body resonator, such as a whole-body antenna, for transmitting radio frequency signals at a wave length .lambda. to induce nuclear magnetic resonance phenomena in the examination subject, and a surface coil for receiving the resulting nuclear magnetic resonance signals. For decoupling the body resonator from the surface coil, a .lambda./4 line is connected to the surface coil. A terminating end of the .lambda./4 line is short-circuited during emission of radio frequency pulses by the body resonator, and is opened during reception of nuclear magnetic resonance signals using the surface coil. An effective detuning of the body resonator is thus achieved during the reception event, and at the same time the transmission event is minimally influenced.

Nuclear magnetic resonance apparatus for the identification of spectra

A tomography apparatus utilizing nuclear magnetic resonance techniques for representing internal cross-sections of an examination subject has a surface coil for acquiring a signal corresponding to the displacement of the nuclear spins of the examination subject from a equilibrium position. The surface coil is annular and has its ends connected to ground through respective capacitances. A tape-shaped high-frequency shielding at least partially surrounds the surface coil.

Nuclear magnetic resonance tomography apparatus

For the representation of images of regions selected from the interior of an examination subject, coils are provided for the application of a primary magnetic field and of magnetic gradient fields to the examination subject. An electrical conductor configuration detects the deflection of the atomic nuclei of the examination subject from their position of equilibrium as a result of high frequency magnetic excitation pulses. The configuration is formed by two interspersed individual conductor configurations adapted for respective different measurement frequencies. Each configuration comprises parallel conductors connected at their ends and arranged in spaced relation to an electrically grounded surface to form a transmission line configuration resonant at a respective one of the measurement frequencies.

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Erlangen, Germany

Ralph Meissner