Abstract: A device has a first control loop (28) with which a frequency RF of an RF generator is synchronized with a resonance frequency F0 of an NMR line. A phase shifter (22) 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 (27) whose input signal comes from a signal extraction stage.

Abstract: A device that comprises an RF generator (29), an NMR transmission (20) and reception system (21) and a first control loop (28), with which the frequency fRF of the RF generator is synchronized with the resonance frequency f0 of an NMR line, wherein, from the signal of the RF generator, a train of excitation pulses (EX) of the repetition frequency fm is generated, with which nuclear spins of a certain resonance frequency of an associated NMR line are excited quasi-continuously (CW) and, in the times between the excitation pulses, the NMR signal is received (AQ), wherein the period time 1/fm is chosen to be much smaller than the relaxation time of the NMR line, preferably shorter than 1/10 of the relaxation time, and the NMR signal UD mixed down into the low-frequency range is used, with the help of the first control loop, to closed-loop-control the value of the transmission frequency (=frequency lock) or the value of the B0 field (=field lock) in such a way that the frequency and phase of the RF generator and

Abstract: 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 (31) for detecting interfering signals (Uin), at least one control loop for processing the detected interfering signals (Uin), and at least one compensation coil (34) to which the detected and processed interfering output signals (Uout) are transferred and which generates a correction field for compensating the interfering signals (Uin), is characterized in that at least one of the control loops comprises a multi-selective filter system (35) 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 (Uin) to be compensated for, wherein the outputs of these filter elements are connected to at least one of the compensation coils (34).

Abstract: 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 (31) for detecting interfering signals (Uin), at least one control loop for processing the detected interfering signals (Uin), and at least one compensation coil (34) to which the detected and processed interfering output signals (Uout) are transferred and which generates a correction field for compensating the interfering signals (Uin), is characterized in that at least one of the control loops comprises a multi-selective filter system (35) 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 (Uin) to be compensated for, wherein the outputs of these filter elements are connected to at least one of the compensation coils (34).