Bruker Biospin Ag

Bruker Switzerland Ag

Michael Schenkel

Werner H Tschopp

Arthur Schwilch

Rolf Hensel

Werner Tschopp

A device has a first control loop () with which a frequency RF of an RF generator is synchronized with a resonance frequency Fof an NMR line. A phase shifter () is provided to rotate the radio frequency phase of the NMR receiver system in the first control loop. The phase shifter is controlled by a second control loop () whose input signal comes from a signal extraction stage.

Device for highly precise synchronization of the NMR transmission frequency to the resonance frequency of an NMR line while taking into consideration a non-constant RF phase

A device for compensating field disruptions in magnetic fields of electromagnets with high field homogeneity, in particular, for stabilizing the H0 field of an MR measuring system, comprising at least one field detector () for detecting interfering signals (U), at least one control loop for processing the detected interfering signals (U), and at least one compensation coil () to which the detected and processed interfering output signals (U) are transferred and which generates a correction field for compensating the interfering signals (U), is characterized in that at least one of the control loops comprises a multi-selective filter system () which comprises one or more parallel connected selective filter elements whose center frequencies can be tuned either once or in an adaptive fashion to the frequency values of the interfering signals (U) to be compensated for, wherein the outputs of these filter elements are connected to at least one of the compensation coils (). The inventive device permits selective detection of periodic field disturbances with high frequency components while a major part of the existing noise is faded out, thereby increasing the SINO.

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Baeretswil, Switzerland

Michael Schenkel