| 摘要 |
PURPOSE:To eliminate a magnetic field inclined lateral component generated by a sample and a sample tube itself, by supplying a current synchronizing with the rotation of the sample, to a current shim device for correcting the degree of uniformity of a magnetic field basing on the rotation detecting output of the sample. CONSTITUTION:The output of a high frequency oscillator 7 is sent as a high frequency pulse to the NMR probe 2 in a magnet 1 for generating a DC magnetic field, through a gate 9 controlled by an observation controlling circuit 8, and irradiated to a sample. A free induction attenuating signal generated from the sample is sent to a data processing device 12 through a demodulating circuit 10 and an A/D converter 11. On the other hand, the detecting signal of a rotation detecting mechanism incorporated in a sample tube rotating mechanism 6 for rotating a sample tube 5 by blowing pressurized air from a compressor 4 is sent to a synchronizing oscillator 19 through a waveform shaping circuit 18. The output of this oscillator 19 is superposed by adding circuits 22, 25 to the direct current supplied to X shim and Y shim of a current shim 3 from DC power sources 21, 24 through a variable phase device 20 and a 90 deg. phase shifter 23. |
